Choose the correct variant. I don’t mind (to have/having) a bite.
She looks forward (to meet/meeting) them.
I want (to visit/visiting) my grandparents on weekend or holidays.
I can’t imagine her (to get/getting) married to Harry.
I’d like to make him (work/working) better.
Let’s stop (to eat/eating) at this restaurant.
We couldn’t help (to laugh/laughing) at Robin Williams’s acting.
How do you prefer (to travel/travelling): by train or plane?
Do you fancy (to eat/eating) out?
It was difficult enough (to learn/learning) to play the guitar.

Let's look at each sentence to choose the correct form of the verb. In English, some verbs are followed by the gerund (-ing form), while others are followed by the infinitive (to + base form). Sometimes, the meaning of a verb can change depending on which form it is followed by.

1. "I don’t mind having a bite." - The verb 'mind' is typically followed by a gerund.

2. "She looks forward to meeting them." - The expression 'look forward to' is always followed by a gerund.

3. "I want to visit my grandparents on weekend or holidays." - 'Want' is followed by an infinitive.

4. "I can’t imagine her getting married to Harry." - 'Imagine' is typically followed by a gerund.

5. "I’d like to make him work better." - The structure 'make someone do something' requires an infinitive without 'to'.

6. "Let’s stop eating at this restaurant." - 'Stop' is followed by a gerund when it means to cease doing an action that is already in progress.

7. "We couldn’t help laughing at Robin Williams’s acting." - 'Help' in the sense of not being able to control oneself is followed by a gerund.

8. "How do you prefer travelling: by train or plane?" - 'Prefer' can be followed by either a gerund or an infinitive without a change in meaning, but the gerund form is more common in this context.

9. "Do you fancy eating out?" - 'Fancy' is followed by a gerund.

10. "It was difficult enough to learn to play the guitar." - 'Difficult' is an adjective that, when describing an action, is usually followed by an infinitive.

So, the correct forms in these sentences are: having, meeting, to visit, getting, work, eating, laughing, travelling, eating, and to learn.