1 . Public health experts kept telling citizens it was of utmost importance that social distancing and hygiene habits ________ amid the pandemic.

A．were to be kept	B．had to be kept
C．must be kept	D．should be kept

2 . —Must the government of Philippines (菲律宾政府) say sorry to China.
—Yes, they ________. Their behaviour has deeply hurt Chinese people.

A．need

B．must

C．can

D．may

3 . 因为出乎意料的暴力事件频发，出租车公司必须向乘客确保出行的安全。（assure）(汉译英）

4 . 选词填空

well off;   be keen on;   be ashamed of;   in all ;     on behalf of ;   refer to

1. They would never _________ that matter again.
2. You should _________ yourself for telling such lies.
3. In addition, a hero must be optimistic and diligent and_________ his hard work.
4. It won't be long before the Chinese people will become _________.
5. Please allow me to thank you for your offer of help _________ my colleagues.

5 . If fish are jumping higher than usual or frogs are croaking more loudly, it________ rain.

A．must

B．may

C．shall

D．need

6 . The designer has tried every possible way to make the robot light, so you_______worry about its weight.

A．must

B．may

C．can't

D．needn't