'not to think' vs 'not thinking'

[Adam Cruge]

Consider the two sentences:
a) Make a habit of not to think of her.
b) Make a habit of not thinking of her.

Which one is the correct sentence? Please explain.

[bhaisahab]

Consider the two sentences:
a) Make a habit of not to think of her.
b) Make a habit of not thinking of her.

Which one is the correct sentence? Please explain.

Would you say "Make a habit of to think of her" or "Make a habit of thinking of her"?

[emsr2d2]

Consider the two sentences:
a) Make a habit of not to think of her. Incorrect
b) Make a habit of not thinking of (or about) her. Correct

Which one is the correct sentence? Please explain.

Sentence b is correct. You make a habit of doing something (or of not doing something).

[Adam Cruge]

Got it. Thank you both of you.

[BobK]

Other contexts require a different response, but for the same reason.

For example 'It's important to think of her' -> 'It's important not to think of her' (not 'It's important not thinking of her.')

And other words can take either: 'It's silly not to think of her' and 'It's silly not thinking of her'.' (To my ear, the second version sounds slightly more informal - especially in the positive version: 'It's silly thinking of her.'

b