Question

1. I felt it my duty to help him.
2. I flet it my duty helping him.

3. I make it a rule to get up at six.
4. I make it a rule getting up at six.

5. I found it easy to memorize the poems.
6. I found it easy memorizing the poems.

7. We consider it foolish of him to try it again.
8. We consider it foolish his trying it again.
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Can we use the gerund instead of the to-infinitive? Are they all grammatical? It seems that the to-infinitive is used more frequently.

Answer 1

while syntactically gerunds are equivalent to infinitives in these uses, in practice, I doubt you will find anyone using the constructions in 2 and 4. I have heard #6. I guess because the word preceding the gerund is an adjective rather than a noun.

#7 and 8 are both common, but more often I have heard 7.

Answer 2

Didn't I already answer this earlier today?