428　laugh, laugh at和smile

1　laugh 表示“笑”，指出声的大笑。

Children are jumping and laughing on the sports ground. 孩子们在操场上又跳又笑。

We all laughed loudly at the joke. 听了那个笑话，我们都大笑起来。

He laughed when he saw it. 他看到那个就笑了。

2　laugh at 意为“嘲笑，因……而笑，对……一笑置之”。

Everyone laughed at his foolish behaviour. 大家都笑他的愚蠢行为。

Don't laugh at those in trouble. 不要嘲笑陷于困境的人。

3　smile 意为“微笑”，通常指不出声的笑。

The old man sat down with a smile on his face. 老人坐了下来，脸上露出了笑容。

She smiled at me. 她向我微笑。

He smiled to welcome us. 他微笑着对我们表示欢迎。