1. Contrasting Gerunds and Infinitives
When I stopped eating ice cream every day, I lost five pounds.
When I stopped to eat ice cream every day, I gained five pounds.
It started raining a few minutes ago. Take an umbrella.
It started to rain a few minutes ago. Take an umbrella.

2. Verbs taking only gerunds
Some verbs take only gerunds. These verbs include avoid, dislike, enjoy, finish, miss, prohibit, resist.
Paul enjoys swimming.
I finished reading the book.

3. Verbs taking only infinitives
Some verbs take only infinitives. These include agree, expect, need, offer, plan, promise, want.
Luke wants to leave.
I expect to receive a letter today.

4. Verbs taking both G and I with no difference in meaning
Some verbs can take both gerunds and infinitives with no change in meaning.
These include begin, continue, hate, love, like, prefer, start
I began feeling sick after I ate Luke’s food.
I began to feel sick after I ate Luke’s food.
It starts snowing in November.
It starts to snow in November.

5. Begin and Start
After continuous forms of begin and start, use an infinitive, NOT a gerund.
I was beginning to feel sick.
*I was beginning feeling sick.
He was starting to get better.
*He was starting feeling better.

6. Verbs that take Both G and I and there IS a difference in meaning
Some verbs can take both gerunds and infinitives, but they have a difference in meaning.
After stop, forget, remember, the gerund refers to something that happened BEFORE the action of the main verb.
The infinitive refers to something that happened AFTER the action of the main verb.

7. Something happened before action of main verb = GERUND
I stopped smoking.
(I was a smoker. Then I stopped.)
He remembered mailing the letter.
(He mailed the letter. Then he remembered doing it.)
Something happened after action of main verb = INFINITIVE
I stopped to smoke.
(I stopped what I was doing. Then I smoked.)
He remembered to mail the letter.
(He remembered the letter. Then he mailed it.)

8. FORGET
The verb forget is usually used with an infinitive. With a gerund, forget is most common in sentences with will never.
I forgot to go to her party. She was mad at me.
First = I forgot Second = I didn’t go.
I’ll never forget going to her party. It was so much fun.
First = I went to the party. Second = I won’t forget it.