Smith ______ a book about China last year, but I don't know whether he has finished it.
| A．has wrote | B．wrote | C．had written | D．was writing |
The cause he had devoted himself to _______ a perfect success.
| A．proving | B．proved | C．was proved | D．has been proved |
Many experts believe that teachers’ development is _____ the key to better education lies.
| A．that | B．what | C．where | D．which |
Evidence has been piled up_____drinking water after getting up in the morning contributes to one’s health.
| A．what | B．which | C．if | D．that |
There is a great deal of research ___that music activities engage different parts of the brain.
| A．indicate | B．indicating | C．to indicate | D．to be indicating |
Teenagers have reached a point in their life_____they are supposed to make decisions of their own for the first time.
| A．which | B．where | C．how | D．why |