Training astronauts______not an easy thing.

admin2015-03-17  25

问题 Training astronauts______not an easy thing.

选项 A、are
B、is
C、were
D、be

答案B

解析 当分词短语作主语时,谓语动词用单数,故选B。
转载请注明原文地址:https://kaotiyun.com/show/NUiK777K
0

最新回复(0)