be on guard是什么意思

双语例句

(1)At the outset, it seemed necessary to be on guard against the other two.

一开始，似乎有必要提防另外两个。

(2)Two soldiers must be on guard all night.

两名战士必须通宵警戒。

(3)I must protect myself and be on guard.

我必须保护自己、保持警惕。

(4)Two soldiers must be on guard all night.

必须有两个士兵整夜站岗。

(5)We should be on guard against such people.

我们应警惕这种人。