Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.
Many questions ________ at the news conference, but he answered none.
The child asked his mother ________ go out to play tennis.
It is the first time that I _______ this kind of moon cake.
_____ catch the first bus, he got up very early this morning.
It was because of bad weather _____ the football match had to be put off.