Question

---The book is borrowed from the library. You ______ your children touch it with their dirty hands.
---Sorry.　

1. A.
   should have let　
2. B.
   needn’t have let　
3. C.
   mustn’t have let
4. D.
   ought not to have let

Answer 1

D
考查情态动词。ought not to have done本不应当做某事。句意：——书借自图书馆，你本不应当让孩子用脏手碰它。——对不起。