Question

Combine the following sentences into a complex sentence with a subordinate adverb clause.
The policemen delayed the drivers. The wrecks were cleared. [Advanced]

• A. The policemen delayed the drivers until the wrecks were cleared.
• B. The policemen didn't delay the drivers.
• C. The policemen delayed the drivers who created the wrecks.
• D. The policemen cleared the wrecks delaying the drivers.

Answer 1

The correct option is A The policemen delayed the drivers until the wrecks were cleared.

An adverb clause is a subordinate clause which does the work of an adverb .It may, therefore, modify some verb, adjective, or sometime another adverb in the main clause.
In this case,
Option A is correct. The policemen delayed the drivers is the principal clause and since the subordinate clause, until the wrecks were cleared, does the work of an adverb by modifying the verb 'delayed' in the principal clause, it's called a subordinate adverb clause.
Option B is incorrect as the meaning of the sentence has been completely changed.
Option C is incorrect because the sentences have been joined by using a subordinate adjective clause and the sense has also been altered.
Option D is incorrect because It's a simple sentence devoid of any subordinating conjunction.