see sb do sth 看到某人做了某事
see sb doing sth 看到某人在做某事
hear sb do sth 听到某人做了某事
hear sb doing sth 听到某人在做某事
以此类推...
I heard someone knocking at the door when I fell asleep. (我入睡时有人正敲门,强调当时正在敲门)
I heard someone knock at the door three times. (听到有人敲门的全过程)
I often watch my classmates play volleyball after school. (此处有频率词often)
(了解)若以上词用于被动语态,须将省略的to还原:
see sb do sth----sb be seen to do sth
hear sb do sth----sb be seen to do sth
以此类推...
We saw him go into the restaurant. → He was seen to go into the restaurant.I hear the boy cry every day. → The boy is heard to cry every day.
2.感官动词look, sound, smell, taste, feel可当系动词,后接形容词。
He looks angry.
His explanation sounds reasonable.
The cakes smell nice.
The dishes taste delicious.
The silk feels smooth.
注意:如果加介词like构成词组,则后不可接形容词,而接名词或代词:
sound like 听起来像...
look like 看起来像...
He looks like his mother.
That sounds like a good idea.
It sounds like great fun.
It smells like a flower.