何时用apear to do,何时用apear to have done?分别要是什么时态背景?请举例说明,一楼，我有见过She appears to have known it.

何时用apear to do,何时用apear to have done?分别要是什么时态背景?请举例说明,一楼，我有见过She appears to have known it. 句首做主语何时用doing 何时用to do somebody was thought to do/ have done.句型中,何时用to do,何时have done 何时用not to do sth 何时用not do sth make sb do与make sb to do的区别何时用do 何时用to do?明白 问：It is ___ sb to do sth.中的“___”何时用of,何时用for? hope to do与hope doinghope to do和hope doing 有什么区别?何时用hope to do,何时用hope doing. need何时为情态动词,何时加to do 何时用现在完成时,何时用一般过去式? weekend何时用单数何时用复数? 助动词何时用be何时用have 角动量何时用mlv何时用jw the secret to 后面动词形式是ing,何时用to do? 何时用does/do 何时用is/are放在疑问句开头那种 何时用do/does/did提问 何时用have/has 提问?经常混乱,很痛苦. 杯酒释兵权,何时用这个词 fruit何时用复数 何时用持续性动词