1.看标志词:

now

例句: They are flying kites now.

right now

例句: Sally is making a call again right now.

look!

例句: Look! Mr. Wang is talking with a student over there.

listen!

例句: Listen! Someone is crying in the next room.

2. 句子 It is+具体几点之后

例句: It is 10 a.m. . We are having an art class in the classroom.

3 根据上下文情境:常见的有

Be quiet.

Don't be noisy here.

Don't talk so loudly.

例句: Be quiet!The baby is sleeping.