MARK THE LETTER A,B,C,OR D ON YOUR ANSWER SHEET TO INDICATE THE SENTENCE THAT BESTCOMBINES EACH PAIR OF SENTENCES IN THE FOLLOWING QUESTION

Câu 19: Mark the letter A,B,C,or D on your answer sheet to indicate the sentence that bestcombines 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 livessleeping.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.