The correct answers are replaced, changed, and checked.
The structure have + something + done shows that you asked or paid someone else to perform an action. The main verb must always be in the past participle form (replaced, changed, checked), no matter if the event happened in the past, present, or future!
Verb
A verb is a word that expresses an action, a state, or an occurrence — and it's the engine of every English sentence. Understanding how verbs work is foundational to everything else in English grammar, from forming questions to building complex sentences.
Verb Forms
Most English verbs have five inflected forms:
- Base form (go, write, climb) — used as an infinitive, imperative, present subjunctive, and present indicative in all persons except third-person singular.
- -s form (goes, writes, climbs) — used for the present tense, third-person singular (she writes).
- Past tense (went, wrote, climbed) — also called the preterite.
- Past participle (gone, written, climbed) — identical to the past tense for regular verbs, but often different for irregular verbs.
- -ing form (going, writing, climbing) — serves as the present participle and gerund.
The verb be is a special case with more forms than any other English verb (am, is, are, was, were, been, being). Modal verbs like can, must, and should have fewer forms than typical verbs.
Main Verbs and Auxiliaries
Verbs in English often appear in combinations: one or more auxiliary verbs paired with a main verb.
- The dog was barking very loudly.
- My hat has been cleaned.
- Jane does not really like us.
The first verb in the combination is the finite verb (it carries tense and agrees with the subject). The rest are nonfinite (infinitives or participles). Notice that these verbs don't always sit next to each other — as in does not really like.
Tense, Aspect, and Mood
English expresses tense (time reference), aspect (how an action unfolds over time), and mood (the speaker's attitude toward the action) mostly through verb combinations rather than word endings. That's why you'll encounter labels like "present progressive" or "conditional perfect" — these are specific tense–aspect–mood combinations built with auxiliaries.
Self-check: If you can change the time of a sentence by swapping one word (She runs → She ran), that word is the verb.
Keep Practising
To build your verb skills from the ground up, try these challenges: Basics. "To be" in Present Tense, Basics. Common Uses of Auxiliary Verbs, and Transitive and Intransitive Verbs.
Participle
Participles are verb forms that do double duty — they help build tenses and voices, but they also work as adjectives and adverbs. Understanding both types of participles is essential for forming correct verb tenses, using the passive voice, and writing more sophisticated sentences.
The Two Participles
English has two participles:
- Present participle — formed by adding -ing to the base verb: doing, running, sleeping. It's identical in form to the gerund, but serves a different function (more on that below).
- Past participle — for regular verbs, it's the -ed form (walked, boiled). For irregular verbs, it varies widely: done, written, sung, gone.
How the Present Participle Is Used
- Progressive tenses: She is reading a book.
- As an adjective: The woman sitting by the window is my boss.
- As an adverb: Looking up from his phone, he noticed the bus had arrived.
- In absolute constructions (with its own subject): The weather being terrible, we cancelled the trip.
Present participles used as adjectives carry an active meaning — an exciting movie is one that excites you.
How the Past Participle Is Used
- Perfect tenses: They have finished the project.
- Passive voice: The email was sent this morning.
- As an adjective: The broken window needs replacing.
- Adverbially: Exhausted from the hike, we fell asleep immediately.
Past participles used as adjectives usually carry a passive meaning — the attached file is one that has been attached. However, past participles of intransitive verbs can have active meaning: fallen leaves (leaves that have fallen).
Participle vs. Gerund
Both the present participle and the gerund end in -ing, but they do different jobs. The participle acts as an adjective or adverb; the gerund acts as a noun.
- ✅ Swimming in the lake, she felt completely free. (participle — describes she)
- ✅ Swimming is her favourite hobby. (gerund — subject of the sentence)
The famous example Flying planes can be dangerous is ambiguous: flying could be a gerund ("the activity of flying planes") or a participle ("planes that fly").
Self-check: If you can replace the -ing word with a noun like "it" or "the activity," it's a gerund. If it describes a noun or tells you more about an action, it's a participle.
Watch Out: Past Tense vs. Past Participle
For regular verbs, the past tense and past participle look the same (walked, played). For many irregular verbs, they differ:
- ✅ I went home early. (past tense)
- ✅ I have gone home early. (past participle)
- ❌ I should have went home early.
If you're unsure, check whether the verb follows a helping word like have, has, or had — if it does, you need the past participle form.
Ready to practise? Try Gerund vs. Participle: Understanding -ing Word Functions, Participle Clauses: Shortening Sentences with -ing and Having + Past Participle, or Participle vs Gerund.
Active and Passive Voice
The active voice (where the verb's subject is understood to denote the doer, or agent), of the denoted action) is the unmarked voice in English.
To form the passive voice (where the subject denotes the undergoer, or patient), of the action), a periphrastic construction is used.
In the canonical form of the passive, a form of the auxiliary verb be (or sometimes get) is used, together with the past participle of the lexical verb. Passive voice can be expressed in combination together with tenses, aspects and moods, by means of appropriate marking of the auxiliary (which for this purpose is not a stative verb, i.e. it has progressive forms available).
For example:
- This room is tidied regularly. (simple present passive)
- It had already been accepted. (past perfect passive)
- Dinner is being cooked right now. (present progressive passive)
The passive forms of certain of the combinations involving the progressive aspect are quite rare; these include the present perfect progressive (it has been being written), past perfect progressive (it had been being written), future progressive (it will be being written), future perfect progressive (it will have been being written), conditional progressive (it would be being written) and conditional perfect progressive (it would have been being written). Because of the awkwardness of these constructions, they may be paraphrased, for example using the expression in the process of (it has been in the process of being written, it will be in the process of being written, and similar).
The uses of these various passive forms are analogous to those of the corresponding tense–aspect–mood combinations in the active voice.
Object
Traditional grammar defines the object in a sentence as the entity that is acted upon by the subject. There is thus a primary distinction between subjects and objects that is understood in terms of the action expressed by the verb, e.g. Tom studies grammar—Tom is the subject and grammar is the object. Traditional theories of sentence structure divide the simple sentence into a subject and a predicate, whereby the object is taken to be part of the predicate. Many modern theories of grammar (e.g. dependency grammars), in contrast, take the object to be a verb argument like the subject, the difference between them being mainly just their prominence; the subject is ranked higher than the object and is thus more prominent.
The main verb in a clause determines whether and what objects are present. Transitive verbs require the presence of an object, whereas intransitive verbs block the appearance of an object. The term complement overlaps in meaning with object: all objects are complements, but not vice versa. The objects that verbs do and do not take is explored in detail in valency theory.
Types
Various object types are commonly acknowledged: direct, indirect, and prepositional. These object types are illustrated in the following table:
| Type | Description | Example |
|---|---|---|
| Direct object | Entity acted upon | Sam fed the dogs. |
| Indirect object | Entity indirectly affected by the action | She sent him a present. |
| Prepositional object | Object introduced by a preposition | She is waiting for Lucy. |
The descriptions "entity acted upon" and "entity indirectly affected by the action" are merely loose orientation points. Beyond basic examples such as those provided in the table, these orientation points are not much helpful when the goal is to determine whether a given object should be viewed as direct or indirect. One rule of thumb for English, however, is that an indirect object is not present unless a direct object is also present. A prepositional object is one that is introduced by a preposition. Despite the difficulties with the traditional nomenclature, the terms direct object and indirect object are widespread.
The term oblique object is also employed at times, although what exactly is meant varies from author to author. Some understand it to be an umbrella term denoting all objects (direct, indirect, and prepositional), whereas others use the term to denote just a prepositional object.
Syntactic Category
While the typical object is a pronoun, noun, or noun phrase, objects can also appear as other syntactic categories, as illustrated in the following table:
| Category | Example |
|---|---|
| Noun (phrase) or pronoun | The girl ate fruit. |
| that-clause | We remembered that we had to bring something. |
| Bare clause | We remembered we had to bring something. |
| for-clause | We were waiting for him to explain. |
| Interrogative clause | They asked what had happened. |
| Free relative clause | I heard what you heard. |
| Gerund (phrase or clause) | He stopped asking questions. |
| to-infinitive | Sam attempted to leave. |
| Cataphoric it | I believe it that she said that. |
Identification
A number of criteria can be employed for identifying objects, e.g: The object follows the subject. Languages vary significantly with respect to these criteria. The first criterion identifies objects reliably most of the time in English, e.g.
Fred gave me a book.
- a. A book was given (to) me. — Passive sentence identifies a book as an object in the starting sentence.
- b. I was given a book. — Passive sentence identifies me as an object in the starting sentence.
The second criterion is also a reliable criterion for isolating languages such as English, since the relatively strict word order of English usually positions the object after the verb(s) in declarative sentences.
The third criterion is less applicable to English, though, since English lacks morphological case, exceptions being the personal pronouns (I/me, we/us, he/him, she/her, they/them).
Verb Classes
Verbs can be classified according to the number and/or type of objects that they do or do not take. The following table provides an overview of some of the various verb classes:
| Transitive verbs | Number of objects | Examples |
|---|---|---|
| Monotransitive | One object | I fed the dog. |
| Ditransitive | Two objects | You lent me a lawnmower. |
| Tritransitive | Three objects | They sold me bananas for two dollars. |
| Intransitive verbs | Semantic role of subject | Examples |
|---|---|---|
| Unaccusative | Patient | The man stumbled twice, The roof collapsed. |
| Unergative | Agent | He works in the morning, They lie often. |
Ergative and object-deletion verbs can be transitive or intransitive, as indicated in the following table:
| Transitive | Example |
|---|---|
| Ergative | The submarine sank the freighter. |
| Object deletion | We have already eaten dinner. |
| Intransitive | Example |
|---|---|
| Ergative | The freighter sank. |
| Object deletion | We have already eaten. |
The distinction drawn here between ergative and object-deletion verbs is based on the role of the subject. The object of a transitive ergative verb is the subject of the corresponding intransitive ergative verb. With object-deletion verbs, in contrast, the subject is consistent regardless of whether an object is or is not present.
B1 | Intermediate
B1 is the intermediate level of the Common European Framework of Reference for Languages (CEFR). It marks the point where you move beyond survival English and start expressing yourself with real independence — describing experiences, explaining opinions, and handling everyday situations without a script.
What a B1 user can do
At this level, you're expected to:
- Understand the main points of clear, standard speech and writing on familiar topics — work, school, travel, hobbies.
- Handle most travel situations in English-speaking environments.
- Produce simple connected text on topics you know or care about.
- Describe experiences, events, hopes, and plans, and give brief reasons and explanations for your opinions.
- Communicate in routine tasks that require a straightforward exchange of information.
What B1 grammar looks like
B1 is where grammar starts to get more layered. You're not just forming basic sentences anymore — you're combining ideas, using different tenses with more precision, and starting to handle structures like the passive voice, modal verbs for necessity and possibility, and gerunds vs. infinitives. You're also expected to build complex sentences with linking words and dependent clauses.
Typical B1 grammar areas include:
- Future tenses — distinguishing will, going to, and the present continuous for future plans
- Passive voice — The report was written yesterday.
- Modal verbs — You should apply early. / She might be late.
- Used to — I used to live in Berlin.
- Verb patterns — knowing whether a verb takes a gerund, an infinitive, or both (I enjoy reading vs. I decided to leave)
What B1 doesn't mean
B1 speakers still hesitate, make grammatical errors, and sometimes struggle with less familiar topics. That's normal. The key difference from A2 is that you can keep a conversation going and get your point across even when things aren't perfect. The step up to B2 involves handling more abstract topics, understanding nuance, and producing more complex, accurate language.
Self-check: Can you tell a friend about a recent trip — what happened, what you liked, and what you'd do differently — without switching to your native language? If yes, you're likely operating at B1 or above.
Ready to find out where you stand? Try Are you B1/Intermediate? Test your English CEFR Level to figure out!, then build your skills with challenges like Basics. Passive Voice, Basics. Modal verbs, and Used to.
Difficulty: Medium
Medium difficulty. Difficulty levels represent author's opinion about how hard a question or challenge is.