In Singapore, the policy(政策) on the mother tongue creates favorable conditions for the various minority groups to their cultures from dying out.
| A．defend | B．reserve |
| C．challenge | D．preserve |
The islands developed on their own for 80 million years and ________ have many rare animals found nowhere else.
| A．soon | B．so | C．early | D．yet |
She is a crazy fan of this singer. ________ she listens to his songs hundreds of times, she will never get tired.
| A．If | B．Unless ． | C．As long as ． | D．Even if |
Everyone in our class was working hard and doing what we could ________ a good university.
| A．enter | B．to enter | C．entering | D．entered |
QQ, ________ you can chat with your friends, makes communication easy.
| A．how | B．where | C．that | D．which |
I was watching the news on TV ________ the power went off.
| A．when | B．as | C．while | D．until ． |