Answer:
Hope this helps :)
Explanation:
1.Please call me as soon as you (get) this message.
2. I'll wait with you at the station until your train (arrive).
3.While you're cleaning the house I (take) the dog out for a walk.
4.You will never be able to run the marathon unless you (start) training.
5.I always get a headache when I (drink) enough water.
