补充题205_#104

cz

104. For some birds the sense of smell appears to play a role in navigation, since pigeons with surgically removed olfactory nerves were found to have increased difficulties in homing.

(A) were found to have increased difficulties

(B) have been found to have increased difficulty

(C) were found to have increasing difficulty

(D) had been found to have increased difficulties

(E) have been found to have increasing difficulties

正确为B。 但是B用的是现在完成式，好像A中用的过去式不是更好嘛？"increased difficulity in" 与 "increased difficulities in"有什么不同嘛？ 谢谢

andrew_li

Since in the tense of the main sentense is present simple, it's more appropriate to use the present perfect in the dependant clause than to use past simple. difficulties is the plural form of difficulty.

cz

I know that difficulties is the plural form of difficulty, but I was wondering why "difficuty" is used in the sentence. Is the reason that only one term is followed by "in". Such "increased difficulty in A" & "increased difficulties in A, B, and C"?

andrew_li

have difficulty in doing sth. is the correct idiom.