Student or Learner
Which one sentence is correct? How will I come to know where to use infinitive and where present participle?
1, I saw him go out.
2, I saw him going out.
As the action seen is relatively short, there is little real difference. If the action seen has any duration, then the bare infinitive suggests you saw the whole action, the gerund that you perhaps saw only part of it.
I saw him cross the road. (I saw him walk from one side to the other)
I saw him crossing the road. (I did not necessarily see him step on to the road at one side or on to the pavement at the other side.)