30. How long do you think it will be _____ we can find a new water source?
Then professor walked onto the platform and seated himself in a chair, ________ for answering questions.
The headmaster has promised us that we shall be told ________ the results of the exam come out.
You can't go out since you haven't finished your homework; ________, it is a stormy night.
The victims suffering from the terrible earthquake have to be provided accommodations if they ________.
I have read the material several times but it doesn’t make any ______ to me.