must过去式和过去分词

must例句

1、We must make good use of the available space.

我们必须充分利用现有空间。

2、And again, we must think of the cost.

再说，我们必须考虑成本。

3、You've been a great help, I must say.

依我看，你真是帮了个大忙啊。