Ответ:

#1

1) Doing exams

2) Eating junk food at cafes

3) Getting back

3) Having fun

4) Looking after

5) Spending a day

#2

1) at swimming

2) in designing

3) for

4) of

5) while

#3

1. Adult people avoid doing sports.

2. Maxim is interested in winning the Olympiad.

3. Meeting friends is interesting.

4. Who is responsible for walking the dog?

5. Little kids are afraid of getting a haircut.