13．Many medical scientists are racing__________time to find a cure for H1N1 as soon as possible

the widespread ________ of this medicaltechnology, more diseases can be discovered and treated at an early stage.

The theory wasn’t accepted by many people when it was first ____, but it proved to be true as time went by.

_____ I saw him, I knew what had happened. [ ]

Oh, you sound just like an American. — I still have trouble expressing myself.