It seems/seemed that从句结构可以改为提升主语（raised subject）结构，即用that从句的主语作主句的主语，that从句的谓语改为不定式与seem构成复合谓语。不定式才有什么形式，与动态动词还是静态动词，以及不定式动作或状态与seem之间的相对时间关系有关。例如：

1 不定式为动态动词表示事件

It seems that he has finished his work.

= He seens to have finished his work. (不定式表示的事件先于seems的时间）

It seems that he left yesterday.

= He seems to have left yesterday. (不定式表示的事件先于seems的时间）

It seems that he is writing a new book.

= He seens to be writing a new book. (不定式表示的事件与seems的时间同时）

It seems that he will come tomorrow.

= He seems to come tomorrow. (不定式表示的事件后于seems的时间）

2 不定式为静态动词表示状态

It seems that he know her.

= He seems to know her. （不定式表示的状态与seems同时）

It seems that he has known her for long time.

= He seems to have known her for long time. （不定式表示截止seems时间之前的状态）

It seems that he already knew her at that time.

= He seems to have already known her （不定式表示seems时间之前的状态）

= He seemed to know her already at that time. （不定式表示seemed时间同时的状态）