一般it做主语时,不会出现it seems to do...而是用it seems that(从句)（其从句的主语才是真正的主语,it只是形式主语）
当人做主语时,才有sb.seems to do/have done...
利用楼上例句：
It seemed that I had caught a cold.
=I seemed to have caught a cold.
there seems to后面一定要加be,其实就是there be结构,中间插入seem to而已.