The song reminded me of the old golden days as soon as it _______.

I don’t know if it _________tomorrow. —Well, if it __________, the school sports meet will be canceled.

It may be 5 or 10 years __________ it is possible for people to find a space station on the moon

In such a fierce competition, aperson has to make every effort if he_______.

Many experts believe that teachers’ development is _____ the key to better education lies