托福词汇：hear, see etc + object + verb form

　　1. object + infinitive or -ing form

　　Hear, see, watch, notice and similar verbs of perception can be followed by object + infinitive (without to) or object + -ing form.

　　I heard him go down the stairs.

　　I heard him going down the stairs. (NOT I heard him went down the stairs.)

　　There is often a difference of meaning. We use an infinitive after these verbs to say that we hear or see the whole of an action or event, and we use an -ing form to suggest that we hear or see an action or event in progress, going on. Compare:

　　----- I saw her cross the road. ( = As I looked, she crossed it from one side to the other.)

　　I saw her crossing the road. (= As I looked, she was crossing it - she was in the middle, on her way across)

　　----- I once heard him give a talk on Japanese politics.

　　As I walked past his room I heard him talking on the phone.

　　----- Watch me jump over the stream.

　　I like to watch people walking in the street.

　　----- I heard the bomb explode. (NOT I heard the bomb exploding.)

　　I saw the book lying on the table. (NOT I saw the book lie.....)

　　A progressive form can suggest repetition.

　　I saw her throwing stones at the other children.

　　After can see/hear (which refer to actions and events that are in progress), only -ing structure is used.

　　I could see John getting on the bus. (NOT I could see John get...)

　　These structures can be used after passive forms of hear and see. In this case, the infinitive has to.

　　He was never heard to say \'thaks you\' in his life. (NOT He was never heard say....)

　　Justice must not only be down; it must be seen to be done.

　　She was seen walking away from the accident

　　Passive forms of watch and notice are not used in this way.

　　2. possessives not used

　　After these verbs, possessives cannot be used with -ing forms.

　　I saw Mary crossing the road. (NOT I saw Mary\'s crossing the road.)

　　3. object + past participle

　　In this structure, the past participle has a passive meaning.

　　I heard my name repearted several times. (My name was repeated.)

　　Have you ever seen a television thrown through a window?

　　This idea of \'action or event in progress\' can be given by a progressive form (being + past participle).

　　As I watched the tree being cut down...

　　I woke up to hear the bedroom door being opened slowly.

　　These structures are not possible after passive forms of hear and see.

　　4. look at

　　Look at can be followed by object+ -ing form, and in American English also by Object + Infinitive

　　Look at him eating!

　　Look at him eat! (US)