A number of people were reported to__in a series of explosions .A number of people were reported to__in a series of explosions on London's transport system on Thursday morning.A.had been killedB.have been killedwhy we choose
问题描述：
A number of people were reported to__in a series of explosions .
A number of people were reported to__in a series of explosions on London's transport system on Thursday morning.
A.had been killed
B.have been killed
why we choose
答
to 动词不定式后加动词原型