Change the following sentence into complex sentence: 'Without your help he can do nothing.'

The original sentence has one main clause and a prepositional phrase, so it is simple. Converting it to complex means turning 'Without your help' into a subordinate clause that begins with a conjunction. Option B does this: 'Unless you help him' is an adverbial clause of condition, and 'he can do nothing' stays as the main clause. The meaning and the negative 'nothing' are both preserved.

• A is a simple interrogative. It is not a complex sentence, and its meaning has shifted.
• C is simple. It only reorders the words and keeps 'without your help' as a phrase.
• D is also grammatically complex, since 'unless you help him' is a subordinate clause. The key usually prefers B because it keeps the original structure and wording ('can do nothing') most closely, which is the standard method in transformation questions.

Core concept: sentence transformation (simple to complex) by converting a phrase into a dependent clause with a suitable conjunction. For Mains, this precision in structure helps in essay and précis writing.

Trap: candidates pick D because it looks like a more formal rewrite. Both B and D are complex, so choose the option that keeps the original wording and meaning closest.