Question

All the books that have been contributed by the neighborhood are known _______ t

All the books that have been contributed by the neighborhood are known _______ to the city public library the other day.
A. being sent
B. to be sent
C. having been sent
D. to have been sent

Answer 1

答案D
第一要表示被动；第二要表示send的动作发生在are known之前；第三，are known/said/reported/believed/supposed之后使用不定式形式。句意为“社区里捐赠的书籍，已在几天前送到市公共图书馆里去了”。