используйте правильную форму (придаточные предложения)
If I (feel) bad I (go) to the doctor.
When my parents (come) back we (go) to watch the competition.
When father (come) home we (have) dinner.
If it (not/ snow) she (go) for a walk.

If I feel I will go to the doctorWhen  my parents come back we will go to watch the competition.When father come home we will have dinner.If it does not snow she will go for a walk.