Mark the letter A,B,C,or D on your answer shee...

Câu hỏi: Mark the letter A,B,C,or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following question.
We spent about one-third of our lives sleeping. We know relatively little about sleep.

A We know relatively little about sleep, as a result, we spend about one-third of our lives sleeping.

B We shall know more about sleep if we spend more than one-third of our lives sleeping.

C We spend about one-third of our lives sleeping so that we know relatively little about sleep.

D Despite spending about one-third of our lives sleeping, we know relatively little about sleep.