Question

Combine the given sentences using an adverb clause subordinator:
I reached the theatre. The movie had already begun. [Intermediate]

• A. For I reached the theater, the movie had already begun.
• B. When I reached the theater, the movie had already begun.
• C. Though I reached the theater, the movie had already begun.
• D. Because I reached the theater, the movie had already begun.

Answer 1

The correct option is B When I reached the theater, the movie had already begun.

Sentences that use an adverb clause subordinator are complex sentences, because the adverb clause is a subordinate clause.
From the options, "When I reached...," is an adverb clause of time, which depends on the main clause. Hence option B is correct.
Option A contains an illative conjunction, "for", which is used in compound sentences to express the relation of inference between the clauses. Hence A is incorrect.
Options C and D contain adverb clauses, but they are not relevant to the main clause. "Though" is used to express contrast and "because" is used to express reason. The given sentences express neither, hence options C and D are incorrect.