Ответ:
1.As soon as I buy tickets I will call you.
2.Unless he read the guidebook, he won't understand what he is looking at.
3.It will be dark by the time you arrive at the hotel.
4.Until we know what the result is, we will not be happy
5.While she will be studying for the exam he will be rebuilding his house.
6.1.Before locking the door I left the house или
6.2.Before I locked the door I left the house
На счет 6 я не уверен, так как предложение выходит немного странного содержания, но 6.1 все же лучше