签到的英文：
book in
Sign In
sign on

参考例句：

Please sign in before entering.
请进门前先签到。

What time do you have to check in?
你什么时候该签到上班？

I usually clock in at 8 o'clock.
我通常8点钟签到。

Every morning when we go swimming, we have to sign in at the Health Club.
每天上午我们去游泳时，都得在健康俱乐部签到。

book是什么意思：
n. 书籍；著作；圣经；有内涵的事物；知识；剧本；账簿；卷，篇
adj. 从书本上学来的；账簿记载的
v. 预订；将…的姓名记在本子上；【英】预订房间 c

subsidiary book
辅助帐簿; 明细帐簿

It was a stupid book.
那是一本无聊的书。

This is the sum of this book.
这就是这本书的要点。

The book is appendixed.
那本书后面有附录。

Is this book yours?
这本书是你的吗？

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？