GERUND OR INFINITIVE?

1)  (1.1)_________________ IS A BAD HABIT. YOU SHOULD STOP (1.2)____________ IT!

1.1  a) SMOKING  b) TO SMOKE  c) SMOKE

1.2  a) DOING        b) TO DO          c) DO

2) I REMEMBER YOU YEARS AGO (2.1)____________________ WITH SALLY. YOU WERE A NICE COUPLE.

2.1 a) DATING    b) TO DATE       c) DATE

3) IF I (3.1)_____________________ TO YOU IT IS BECAUSE IS THE BEST FOR YOU.

3.1 a) SPEAKING  b) TO SPEAK    c) SPEAK

4) IT IS A GOOD DAY (4.1)_________________________________ SIGHTSEEING!

4.1 a) GOING         b) TO GO          c) GO

5) I HATE (5.1)_____________________________ THIS!

5.1 a) DOING         b) TO DO          c) DO