A. begins B. having begun D. beginning D. begun
it is 做句子成分时 可以不遵循主从句主语一致的原则吧!?
一般还是遵循主从句主语一直原则的,这里的 it 指前面主句的主语 the reasearcher。有时也有差异。例如:If ( it is ) possible, we will do it tomorrow. If (it is) necessary, I will do it.