sign up的意思是跟…签订合同; 报名，sign in的意思是通过签字（使）取得入场权; 签到; 画到。

一、sign up

英 [sain ʌp] 美 [saɪn ʌp] 跟…签订合同; 报名;双语例句1. He has posted a sign up that says \\\"No Fishing\\\" 他已经张贴了一张“禁止钓鱼”的告示牌。2. They manage to sign up all the best performers. 他们设法跟所有最佳演员签订合同.3. He was not the only one to sign up. 报名参加的不光是他一个人.4. Can I sign up for this course in advance? 我能事先申请上这一课程 吗 ?5. You don\'t sign up for life, you know. 你用不着参加一辈子的, 你知道罢?

二、sign in

英 [sain in] 美 [saɪn ɪn] 通过签字（使）取得入场权; 签到; 画到;双语例句1. All the participants were required to sign in as they entered the hall to attend the meeting. 出席会议的人在进入大厅前均须签到.2. In the meantime, would you sign in and register your ability? 同时你能签下表格以便登记你的超能力 吗 ?3. Clerk : Yes, you can\'t miss it. There\'s a big sign in front of it. 对, 你不会错过的. 酒家正门挂着一块很大的招牌.4. It imply the illegal word sign in the data. 数据中含有非法字符.5. Every student must sign in when he comes back to the college. 每个学生回到学校都必须签到.

sign up和sign in的区别：

1、sign up 的意思是注册报名， 跟…签订合同。

2、sign in 的意思是登录，签到，通过签字（使）取得入场权，画到。拓展资料sign up的用法1、He signed up as a steward with P& O Lines 他签约了P&O航运公司，成为了一名乘务员。2、He saw the song\'s potential, and persuaded the company to sign her up. 他看到了这首歌的潜力，就说服公司和她签约。

3、Lisa: I\'ll sign up tomorrow. 丽莎：我明天就要去报名了。

4、Can I sign up for this course in advance? 我能事先申请上这一课程吗？

5、Maybe you and me should sign up. 也许你和我也可以去登记。sign in的用法1、I signed in and crunched across the gravel to my room. 我签到后嘎吱嘎吱走过石子路来到我的房间。2、All the participants were required to sign in as they entered the hall to attend the meeting.出席会议的人在进入大厅前均须签到。3、You can sign in right there. 你可以就签在那。4、I put the negation sign in front of that. 我在前面写上否定的标志。5、The flow then continues as in the Sign in process. 然后该流将像在“登录”流程中那样继续进行。

so...as一般用于否定句和疑问句，而as...as一般用于肯定句。so as意为只要，用于否定句和疑问句，翻译成像…般那样。as...as意为和...一样，表示同级的比较。使用时要注意第一个as为副词，第二个as为连词。

He crept in so as not to disturb his sleeping parents.

　　他蹑手蹑脚地走进去，以免惊醒熟睡的`父母。

　　She had put her hair up so as to look older.

　　她把头发盘起来以便让自己看起来更成熟些。

　　Services must be structured so as to avoid pitfalls.

　　服务业必须形成层次结构以免隐患。