The research is so designed that once _____ nothing can be done to change it.
#84615
A
begins
B
having begun
C
beginning
D
begun
推荐题目
Only when he apologizes for his rudeness _____ to him again.
#80662
A
I will speak
B
will I speak
C
do I speak
D
I speak
They finally managed to climb to the top,but __then. 
#83935
A
went the children down the hill
B
down the hill did the children go
C
down the hill went the children
D
down the hill the children went