Надо выерите из скобок правильный ответ what (he/buy) you for your birthday? what time (they/leave) the party? what (you all/have) for supper?

Вы не указали время!
Если речь о времени то:
What did he buy you for your birthday?
What time did they leave the party?
What did you have) for supper?
Если будущее
What will he buy you for your birthday?
What time will they leave the party? 
What will you have for supper?