★ sign

① [C]符号

a plus sign 加号

② n. 指示牌;标记

a road/ traffic sign:道路/交通标识

The sign says＂ No smoking”告示牌上写着“禁止吸烟”。

③ [(头、手、眼等的)示意动作;手势

He made a thumb- up Sign.他竖起大搏指。

sign language手语

④ n.迹象;征兆( indication)

The rainy weather showed no sign of improving.

雨还在下，没有转晴的迹象。

⑤ v. 签(名;签字(于信、文件等)

Sign an agreement/ a contact签协议/合同

⑥ v. 示意;以手势表示( signal)

The teacher signed me to enter.老师打手势示意我进来。

▲sign up(for)报名参加(课程等);登记注册:

sign up for the course in advance

提前报名参加课程

I＇m ready to sign up for the mid July group.

我准备报名参加7月中的那个团。

★派生词：signal

①n. 信号;信号灯:

This was a signal for him to continue.这是一个让他继续的信号。

②v. 发信号;示意;表明;标志着

The bell signalled that school was over:铃声响起放学了。

★派生词：signature n.署名;签名:

add/ write one’s signature签字