1.
You must keep silent.
你们必须保持安静。
2.
The precision instrument must be kept free from dust.
精密仪器必须保持无尘。
3.
She knew she must keep calm.
她知道她必须保持冷静。
4.
You decided what to do yourself and, if necessary, you lead the crowd.
“你必须保持主见，必要时，破浪而行。”
5.
Mother is sleeping. We must keep quiet.
妈妈在睡觉，我们必须保持安静。
6.
You must stay wide-awake against possible dangers.
你必须保持警惕,防止可能的危险。
7.
The room for developing photographs must be kept dark
照片显影房必须保持黑暗。
8.
Whatever may happen, you must keep calm.
不论什么事发生，你必须保持冷静。
9.
We must keep to the style of hard struggle and plain living.
我们必须保持艰苦奋斗的作风。
10.
Keep up appearances whatever you do
作事休问好歹，体面必须保持。
11.
To start with, the computer room must be kept very clean.
首先，计算机工作室必须保持清洁。
12.
Mr. Elton must compose his joyous looks.
厄尔吞先生必须保持他欢乐的神色。
13.
You have to keep in touch with your parents.
你必须和双亲保持联系。
14.
The retention period must be less than the retention period for the distribution database.
该保持期必须小于分发数据库的保持期。
15.
You must keep fair with them.
你必须同他们保持友好关系。
16.
We must try to keep up a consistently high standard.
我们必须始终努力保持高标准。
17.
We must try to keep all lines of communication open.
我们必须尽量保持通讯全线畅通无阻。
18.
We should keep the measuring tool clean.
我们必须使量具保持干净。