签字的英文：
sign

参考例句：

An illegible signature
难以辨认的签字.

Attest a signature
对签字作见证.

Not valid until signed
未签字无效

validate a passport
使护照生效(在护照上签字)

A contract is invalidated if only one party signs it.
如果只有一方签字，契约即无效。

We entered into a solemn treaty to defend Belgium, but our signatures did not stand alone there.
我们签订过一项保卫比利时的光荣条约，但是在条约上签字的不仅是我们。

Witness a signature,treaty,will
为一签字、条约、遗嘱签字作证.

Please sign your name here.
请您在这儿签字。

The bond was signed jointly and severally
证书上有联名签字。

In witness whereof,I set my hand.
我作为证人签字。

sign是什么意思：
n. 迹象；预兆；记号，符号；手势；信号，暗号
v. 签名，签署；示意；打手势；用信号表示

This is a superscript sign.
这是个标在上方的符号。

This is a hopeful sign.
这是一个乐观的信号。

Scorpio is an Autumn Zodiac Sign（ as are the Signs of Libra and Sagittarius）。
天蝎：黄道十二宫的第八宫，每年10月23日前后太阳到这一宫。

The teacher signed to us to sign our names on the papers.
老师示意我们把自己的名字写在试卷上。

What does the sign figure?
这标志象征着什么？