________ it is true that a student's most important goal is to do well in his or her studies，it doesn't need to be the only goal.
| A．When | B．As | C．While | D．Before |
I waited for her at the bus station for two hours, but she never______.
| A．turned on | B．turned to | C．turned up | D．turned down |
Scientists have created GM tomatoes which ______ fresh for 45 days, three times as long as normal tomatoes.
| A．are stayed | B．have been stayed | C．stay | D．stayed |
It is not until we know more about the situation ______ we are able to improve it.
| A．that | B．what | C．when | D．which |
— I hear that Mary is ______ to stay with us for a few days. —That’s great.
| A．Maybe | B．possible | C．likely | D．probable |
It was between 1830 and 1835 ______ the modern newspaper was born.
A how B that C which D because