Use the gerund.
1. You must be joking (make) me a proposal like that.
2. After that disgusting scene, he avoided (see) his family.
3. The parents couldn’t help (smile) at their child’s earnestness.
4. I think you made a mistake (come) here.
5. She thought it was silly to go on (waste) the best years of her life looking after the elderly people.
6. Why do you avoid (see) me?
7. We insist on (send) him there at once.
8. He showed no sign of (know) them.
9. He had the habit of (joke) at the wrong moment.
10. He hated (remind) people of their duties.
11. The matter is not worth (speak of).
12. In (discuss) the problem they touched upon interesting items.