There are five types of subordinate clauses in English: the subject, the predicative, the attributive, the object and several types of adverbial clauses.
In English grammar, all the clauses are subdivided into three main groups: noun clauses, adjective clauses and adverb clauses.
The Noun clauses include three types of subordinate sentences such as the subject clause, the predicative clause and the object clause. Usually in subordinate clauses we use the direct word order but in some cases we may face a particular version of inversion. Also, different subordinate clauses need to be introduced by different introductory words which cannot be omitted.
Try the challenge to figure out what all this is about!
Correct Answers
Had Romeo known about Juliette's potion, he would not have killed himself.
This is a conditional with had instead of if (You can also say If Romeo had known...), so there is inversion. You put the (first) auxiliary verb before the subject, Had Romeo, and then the rest of the sentence stays the same. The second part is a normal clause where the verbs follow the subject he would not have killed. Not goes after the first auxiliary verb. Had Romeo known about Juliette's potion is the subordinate clause.
The lights go down. The play will start.
Make a complex sentence.
The play will start after the lights go down.
The play will start after the lights go down.
after the lights go down is the dependent clause. It indicates a condition. You can also start with it too, but then you need a comma: After the lights go down, the play will start.
Choose the correct order.
Cody had just left when his boss arrived.
Cody had just left when his boss arrived. Cody had just left is the independent clause, when his boss arrived is the dependent clause. when signals a subordinating conjunction.
- Correct! he would be back at work in six weeks can be replaced by this, and is a noun phrase. It functions as a direct object.
- Incorrect. Subject/Verb/Object: Morgan/thought/.... The object is a noun phrase, but it follows the same word order (S/V/Oplace|Otime): he/would be/in the swimming pool/at six o'clock. (Morgan thought he would be in the swimming pool at six o'clock)
- Correct! Normal word order: Subject/Verb/Object: The taxi driver/reckoned/.... What did he reckon? That the journey would take 30 minutes. This is a noun phrase, and it takes normal word order.
- Incorrect - You probably spotted that one! What should it be? Use normal word order to make an independent clause, with Subject/Verb/Object: Louis/thought/(that/he/would be staying/in a nice hotel).
Damage was done. It was unclear who will pay for it.
Make a complex sentence.
Who was going to pay for the damage was unclear.
Who was going to pay for the damage was unclear.
This is an example of a relative clause starting with who: It functions as a subject - It is unclear.
Choose the correct order.
A phone was left on the bar. Someone came to pick it up.
Someone came to pick up the phone that was left on the bar.
Someone came to pick up the phone that was left on the bar.
That was left on the bar is the dependent clause saying something about the phone. The phone is it, so you use that to introduce it. The rest of the sentence uses normal word order.
The boy swallowed a coin. He went to hospital.
Create a correct sentence.
The boy who swallowed a coin went to hospital.
The boy who swallowed a coin went to hospital.
The boy who swallowed a coin is the dependent clause in the complex sentence. who swallowed a coin says more about the boy, so it becomes part of the subject. The rest of the sentence follows normal order.
- Correct! The letters that Mark sent her is the object in this sentence.
- Who is for people. Letters are things, so you use that instead.
- Incorrect - the letters that sent Mark follows normal word order: Subject (the letters) / Verb (sent) / Object (Mark) - this cannot be true (letters cannot send anything!).
The two parts of the sentence can be used on their own (The weather is nice/I am going for a swim later), this means there is no subordination.
Correct! Words like because signal that there is a subordinate clause. Because the weather is nice is the subordinate clause.
- Correct! Use that to link to the noun-clause that your shoes were left by the door.
- Incorrect order or wrong meaning. I know that your shoes were left by the door.
- Incorrect order. You need to start with the subject + verb, which is I know. Then follow on asking What do I know? to get the object: Answer that your shoes were left by the door - a noun phrase that forms the object of the verb know. You end up with I know that your shoes were left by the door.
- Correct! You can leave out that - the meaning is still clear.
- Incorrect. Which is incorrect here, it needs to be that. You can create a similar sentence using which of...: I know which of your shoes were left by the door but it means something different. (I know you have more shoes. You left one pair by the door. I know what they look like.)
Clause
- I missed the bus. — ✅ independent clause (stands alone)
- Because I overslept. — ❌ fragment (dependent clause, can't stand alone)
- Because I overslept, I missed the bus. — ✅ dependent + independent = complete sentence
- I missed the bus, and I was late. — ✅ two independent clauses joined by and
A clause is a unit built around a verb with a subject. Independent = can stand alone. Dependent = needs an independent clause to complete it.
Test: does the group of words have a subject + verb AND can it be a sentence on its own? Yes → independent clause. Has a subject + verb but feels incomplete → dependent clause.
Relative clause
- ✅ The man who called is my uncle. — restrictive (essential: which man?)
- ✅ My uncle, who lives in Paris, called. — non-restrictive (extra info, commas)
- ❌ My uncle that lives in Paris — wrong (that can't introduce non-restrictive)
- ✅ The book that I read = The book I read — restrictive (pronoun optional)
Relative clauses modify nouns using who/whom/whose/which/that or where/when/why. Restrictive = essential, no commas, that OK. Non-restrictive = extra, needs commas, uses which/who (never that).
Rule: if you can remove the clause and still know which noun is meant → non-restrictive (commas). If removing it makes the noun ambiguous → restrictive (no commas).
Independent clause
- ✅ I have enough money. — independent clause (complete thought, stands alone)
- ✅ She laughed. — independent clause (subject + verb + complete)
- ❌ Because I was tired. — NOT independent (dependent clause)
- ✅ I left early, and she stayed. — two independent clauses joined
An independent clause has a subject + verb + complete thought. It can be a sentence on its own. Two independent clauses make a compound sentence when joined by a conjunction or semicolon.
Test: does it have a subject, a verb, and feel complete? → independent clause. Does it feel like it needs more? → dependent clause or fragment.
Dependent clause
- ❌ Because I was tired. — fragment (dependent clause standing alone)
- ✅ I left early because I was tired. — attached to independent clause
- ✅ The man who called is my uncle. — relative clause (modifies man)
- ✅ If you're ready, let's go. — conditional dependent clause
A dependent clause has a subject + verb but cannot be a complete sentence. It starts with a subordinating word (because, if, when, although, who, which) and must attach to an independent clause.
Test: does the clause start with a subordinator and feel incomplete on its own? → dependent clause. On its own, it's a fragment — attach it to a main clause.
Complex sentence
- ✅ Because I overslept, I missed the bus. — dependent clause (reason) + independent
- ✅ The man who called is my uncle. — relative clause inside the sentence
- ✅ If it rains, we'll stay inside. — conditional dependent + independent
- ❌ Because I overslept. — fragment (dependent clause alone)
A complex sentence pairs an independent clause with one or more dependent clauses linked by subordinating conjunctions (because, although, if, when) or relative pronouns (who, which, that).
Pattern: independent clause = the main point. Dependent clause = the background, reason, or condition. Move the dependent clause around for emphasis.
Sentence
- She left. — simple (one independent clause)
- She left, and he stayed. — compound (two independents)
- She left because she was tired. — complex (independent + dependent)
- She left because she was tired, and he stayed. — compound-complex
A sentence = one or more clauses forming a complete thought, ending with terminal punctuation. Four types based on clause structure: simple, compound, complex, compound-complex.
Minimum requirement: at least one independent clause with a subject + finite verb. Without that → fragment.
B1 | Intermediate
- ✅ If I had more time, I would travel more. — second conditional
- ✅ The bridge was built in 1920. — passive voice
- ✅ She said she was tired. — reported speech with backshift
- ✅ Although it rained, we enjoyed the trip. — complex sentence with concession
These are B1 patterns — the CEFR intermediate level. At B1 you link ideas, use passive voice, handle reported speech, and manage second conditional — enough for travel, work basics, and everyday independence.
Marker: if you can explain why something happened and follow a news story, you're B1.
Medium
- If I were you, I would apologise. — one rule (second conditional), but distractors like was tempt you
- Answers require active thought, not instant pattern recognition
- Vocabulary and context are realistic, not artificially simplified
- Usually tests one rule, but the wrong answers are plausible
Medium marks middle-difficulty challenges: A2–B1, one rule tested, but with realistic distractors that require genuine understanding.
Use "Medium" when Easy feels too obvious but Hard feels overwhelming. This is where most productive learning happens — the sweet spot of difficulty.