Help Dr. Oops complete his slightly embarrassing lab report by dragging the right verb forms to the gaps.
As a basic rule of physics, if you heat ice, it melts immediately. Unfortunately, if I had remembered to close the lab freezer yesterday, my expensive ice cream cake would not have turned into a sad puddle!
As a basic rule of physics, if you heat ice, it melts immediately.
This is a Zero Conditional sentence. We use "if + present simple" (heat) and the "present simple" (melts) in the main clause to state general truths or scientific facts.
Unfortunately, if I had remembered to close the lab freezer yesterday, my expensive ice cream cake would not have turned into a sad puddle!
This is a Third Conditional sentence. We use "if + past perfect" (had remembered) and "would have + past participle" (would not have turned) to talk about a hypothetical situation in the past and its imaginary past result.
Conditional Sentence
As is typical for many languages, full conditional sentences in English consist of a condition clause or protasis specifying a condition or hypothesis, and a consequence clause or apodosis specifying what follows from that condition. The condition clause is a dependent clause, most commonly headed by the conjunction if, while the consequence is contained in the main clause of the sentence. Either clause may appear first.
Different types of conditional sentences (depending largely on whether they refer to a past, present or future time frame) require the use of particular verb forms (tenses and moods) to express the condition and the consequence. In English language teaching the most common patterns are referred to as first conditional, second conditional and third conditional; there is also a zero conditional and mixed conditional.
Present
Present tense is used, in principle, to refer to circumstances that exist at the present time (or over a period that includes the present time) and general truths. However the same forms are quite often also used to refer to future circumstances, as in "He's coming tomorrow" (hence this tense is sometimes referred to as present-future or nonpast). For certain grammatical contexts where the present tense is the standard way to refer to the future, e.g., conditional sentences and dependent clauses. It is also possible for the present tense to be used when referring to no particular real time (as when telling a story), or when recounting past events (the historical present, particularly common in headline language). The present perfect intrinsically refers to past events, although it can be considered to denote primarily the resulting present situation rather than the events themselves.
The present tense has two moods, indicative and subjunctive; when no mood is specified, it is often the indicative that is meant. In a present indicative construction, the finite verb appears in its base form, or in its -s form if its subject is third-person singular. (The verb be has the forms am, is, are, while the modal verbs do not add -s for third-person singular.)
Past
Past tense forms express circumstances existing at some time in the past, although they also have certain uses in referring to hypothetical situations (as in some conditional sentences, dependent clauses and expressions of wish). They are formed using the finite verb in its preterite (simple past) form.
Certain uses of the past tense may be referred to as subjunctives; however the only distinction in verb conjugation between the past indicative and past subjunctive is the possible use of were in the subjunctive in place of was.
Note also that in certain contexts past events are reported using the present perfect.
Future
English is sometimes described as having a future tense, although since future time is not specifically expressed by verb inflection, some grammarians identify only two tenses (present or present-future, and past). The English "future" usually refers to a periphrastic form involving the auxiliary verb will (or sometimes shall when used with a first-person subject). There also exist other ways of referring to future circumstances, including the going to construction, and the use of present tense forms. For particular grammatical contexts where the present tense substitutes for the future, see conditional sentences and dependent clauses. For discussion and comparison of the various ways of making future reference in English, see going-to future.
For specific uses of future constructions formed with will/shall, see future.
Future-in-the-past
A "future-in-the-past" tense (or form) is sometimes referred to. This takes essentially the same form as the conditional, that is, it is made using the auxiliary would (or sometimes should in the first person).
This form has a future-in-the-past meaning in sentences such as She knew that she would win the game. Here the sentence as a whole refers to some particular past time, but would win refers to a time in the future relative to that past time.
Perfect
The perfect aspect is used to denote the circumstance of an action's being complete at a certain time. It is expressed using a form of the auxiliary verb have (appropriately conjugated for tense etc.) together with the past participle of the main verb: She has eaten it; We had left; When will you have finished?
Perfect forms can also be used to refer to states or habitual actions, even if not complete, if the focus is on the time period before the point of reference (We had lived there for five years). If such a circumstance is temporary, the perfect is often combined with progressive aspect.
The implications of the present perfect (that something occurred prior to the present moment) are similar to those of the simple past, although the two forms are generally not used interchangeably – the simple past is used when the time frame of reference is in the past, while the present perfect is used when it extends to the present.
For all uses of specific perfect constructions, see the sections on the present perfect, past perfect, future perfect and conditional perfect.
By using nonfinite forms of the auxiliary have, perfect aspect can also be marked on infinitives (as in should have left and expect to have finished working), and on participles and gerunds (as in having seen the doctor).
Note that while all of the constructions referred to here are commonly referred to as perfect (based on their grammatical form), some of them, particularly nonpresent and nonfinite instances, might not be considered truly expressive of the perfect aspect. This applies particularly when the perfect infinitive is used together with modal verbs: for example, he could not have been a genius might be considered (based on its meaning) to be a past tense of he cannot/could not be a genius; such forms are considered true perfect forms by some linguists but not others.
Perfect Progressive
The perfect and progressive (continuous) aspects can be combined, usually in referring to the completed portion of a continuing action or temporary state: I have been working for eight hours. Here a form of the verb have (denoting the perfect) is used together with been (the past participle of be, denoting the progressive) and the present participle of the main verb.
In the case of the stative verbs, which do not use progressive aspect, the plain perfect form is normally used in place of the perfect progressive: I've been here for half an hour (not I've been being here...).
Simple
"Simple" forms of verbs are those appearing in constructions not marked for either progressive or perfect aspect (I go, I don't go, I went, I will go, etc., but not I'm going or I have gone).
Simple constructions normally denote a single action (perfective aspect), as in Brutus killed Caesar, a repeated action (habitual aspect), as in I go to school, or a relatively permanent state, as in We live in Dallas. They may also denote a temporary state (imperfective aspect), in the case of stative verbs that do not use progressive forms.
Modal Verb
English has the modal verbs can, could, may, might, must, shall, should, will, would, and also (depending on classification adopted) ought (to), dare, need, had (better), used (to). These do not add -s for the third-person singular, and they do not form infinitives or participles; the only inflection they undergo is that to a certain extent could, might, should and would function as preterites (past tenses) of can, may, shall and will respectively.
A modal verb can serve as the finite verb introducing a verb catena, as in "he might have been injured then". These generally express some form of modality (possibility, obligation, etc.), although will and would (and sometimes shall and should) can serve – among their other uses – to express future time reference and conditional mood.
Humor
Humor is subjective, but at least the author tried.
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.