These machines must ______ before they are used.

admin2009-08-17 30

问题 These machines must ______ before they are used.

选项 A、check
B、be checked
C、are checked

答案B

解析仍然是考查被动语态，注意must 是情态动词，后面应接动词原形be。

转载请注明原文地址:https://kaotiyun.com/show/MvSd777K

公共英语一级笔试

相关试题推荐

随机试题

最新回复(0)