问题

Scientific experiments __________ by students without the teachers’ instructions can be dangerous
A:carry out
B:carrying out
C:carried out
D:carrying
B:carrying out
C:carried out
D:carrying
正确答案是:
同类题型
nter calmly picked up his gun,tookthe aim and fired, ______ the beast
-Excuseme, does Mr Smith’s son live here-He_________ be here, but he has moved.
Do you know everyone from Class One-Er…, I know some of _______.
I listened carefully to his long boring speech, but could not ________ what he was talking about.