I have no idea _______ we can do with these waste materials.
_____ it rain tomorrow, we would have to _______ the picnic.
-- Do you mind if I keep pets in this building? --- ___________.
It is very important that you _______ for this examination.
The car accident on the main road the other day ________ the careless driving of a driver.
The poem did not have an appropriate ending, _________ she would have won the competition.