Question

【题目】The flu(流感) is so harmful that people _________ go to public places.

A. not warn toB. warn not toC. are not warned toD. are warned not to

Answer 1

【答案】D

【解析】

句意“流感是如此地有害，以至于人们被警告不要去公共场所”。根据句意可知，主语people和warn之间为被动be done，排除A和B；warn sb to do sth警告某人做某事，变为否定为warn sb not to do警告某人不要做某事，故选D。