see hear watch notice find make被动语态后是不是一定要加to？

be seen
be heard
be watched
be noticed
be found
be made

使用时要注意:
在主动语态中,make , let , hear , see , watch , notice 等词,其后跟省略to的动词不定式(动词原形),在变为被动语态时,必须还原动词不定式符号to.如:

We heard him sing this song in the room.
He was heard to sing this song in the room.

The boss made him work 14 hours a day.
He was made to work 14 hours a day.

I see him walk to school
He is seen to walk to school.

很正确 因为他们是及物动词
he was seen playing with a girl.
may i made myself heard?

不一定
比如make,be made of或者be made into都可以,要看具体情况