Verbs can also be used after other words:
In such places verbs can have one of these 3 forms:
Some words can be followed by two or three of these forms - sometimes with a change in meaning, sometimes not:
We recommend checking in a good dictionary what forms can follow the word that you want to use.
Verbs in such positions don't change in different tenses:
But we can add the Perfect and the Progressive:
Similarly in the past and the future:
We need to remember that various verbs can have various meanings:
In such situations the Perfect doesn't refer to something before now, but before the "default" time.
The Perfect is usually optional with -ing forms:
But in some situations it helps clarify the meaning: