There are some sentences that do not take infinitive, for example :
Mrs Crump watched him drive off.
I have never heard her say a kind word.
Please tell me what meaning these sentences convey. Does the infinitive sentence, without to, informs about the completion of an action? I am confused.
Please give me a full explanation since I always commit mistake in writing these kinds of sentences and my teacher corrects me, however, I never dare to ask the explanation from my teacher. Please help me.
I think it’s important to know that the infinitive of a verb isn’t necessarily with the preposition ‘to’. In other words ‘go’ ‘take’ speak’ and so on are infinitives. Some verbs are followed by the infinitive of another verb with the preposition as: He tried to work hard. In that sentence the infinitive ‘work’ is the object of the preposition ‘to’. In your examples:
Mrs Crump watched him drive off.
I have never heard her say a kind word.
You are right in saying that ‘drive’ and ‘say’ are both completed actions in those sentences.
‘drive’ and ‘say’ are both infinitives and are the objects of ‘watched’ and ‘heard’.
‘Bare infinitive’ is imply an infinitive without a preposition - you could just as well call it ‘pure infinitive’ as it’s not really relevant here. I tried to explain that the infinitive can be the object of another verb or the preposition ‘to’. You can say: I want to go or I can go because ‘can’ isn’t followed by a preposition.
Your other point is about the difference between the infinitive or the gerund (ing form)
‘I heard the bell ring’ means you heard the sound of the bell and then it stopped. ‘I heard the bell ringing’ means you heard the bell continue to ring.