the maths problem isn't very easy and it is difficulta to finishb to finish it
问题描述:
the maths problem isn't very easy and it is difficult
a to finish
b to finish it
答
选a finish的宾语就是前面的主语it, 所以不需要加it
答
关于主语the maths problem isn't very easy and it is difficult to finish.
关于形式主语
it is difficult to finish it.
答
a.
因为后面那句话是 it is difficult 已经有了主词 (it)
答
The maths problem isn't very easy and it is difficult to finish it.
解析:it is difficult _____中it为形式主语,真正的主语是不定式to finish it. 即:To finish it is difficult.