一道sat语法IS题.When in 1833 a london carpenter designed the first pre_英语解答

一道sat语法IS题.
When in 1833 a london carpenter designed the first prefabricated house,( making certain that a single person can) carry any of the precut panels from which it was assembled.
A>making certain that a single person can
B>making certain that a single person could
C>He makes certain that a signle person can
d>he made certain that a single person could
e>he has made certain that a single person could
为什么不是b而是d?

人气：333 ℃　时间：2020-05-11 22:08:24

解答

这是个时间状语从句、从句中主语是a london carpenter、主句就应该用相应的代词he、如果用现在分词就缺少主语了、是不完整句子里的知识点、我语法差。。再问一下哈，如果用he开头为什么不会成为run on呢？