[求助]无法想通的Sec20 - 19

1.                             As the etched lines on computer memory chips have become thinner and the chips’ circuits more complex, both the power of the chips and the electronic devices they drive have vastly increased.fficeffice" />

(A) the chips’ circuits more complex, both the power of the chips and the electronic devices they drive have

(B) the chips’ circuits more complex, the power of both the chips and the electronic devices they drive has

(C) the chips’ circuits are more complex, both the power of the chips and the electronic devices they drive has

(D) their circuits are more complex, the power of both the chips and the electronic devices they drive have（B）

(E) their circuits more complex, both the power of the chips and the electronic devices they drive have

答案是B,难道不应该是A吗？？？？