Stop! You can never touch this machine when it ________, it is very dangerous. 
#102729
A
has been operated
B
will be operated
C
is operated
D
is being operated
推荐题目
I _____ when it began to rain.
#103379
A
was about to going out
B
was in the point of going out
C
was on the point of going out
D
both A and C
He hasn't come yet.What do you consider _______ to him?
#104390
A
happens
B
has happened
C
happening
D
to happen
Why don’t you try on this jacket? It ____ nice on you.
#100701
A
looks
B
looked
C
will look
D
has looked