Identify the choice which features an adverbial clause accompanied by an independent clause. A) I mentioned in my lecture last night that Shakespeare's life is largely unknown. B) As I mentioned in my lecture last night, Shakespeare's life is largely unknown. C) I mentioned this in my lecture last night: Shakespeare's life is largely unknown. D) I mentioned in my lecture last night; Shakespeare's life is largely unknown.

B). As I mentioned in my lecture last night, Shakespeare's life is largely unknown.

Explanation:

An adverbial clause consists of a subject and a predicate and exemplifies a dependent clause that is functioning as an adverb in the sentence which could modify or describe the verb, adjective or other adverbs. These phrases often begin with subordinating conjunction as presented in the option B. The choice featuring an adverbial clause is option B as it contains "As I mentioned in my lecture last night" which is illustrating the dependent clause and being followed by the independent clause "Shakespeare's life is largely unknown".

B) As I mentioned in my lecture last night, Shakespeare's life is largely unknown.

Explanation:

An adverb clause begins with a subordinating conjunction.

The subordinating conjunction As introduces the adverb clause As I mentioned in my lecture last night and joins it to the main clause Shakespeare's life is largely unknown.