1.You haven't signed up for any extracurriculars.
你没有报名参加任何课外活动。

sign up
报名、注册

I'm thinking of signing up for a yoga course.
我在考虑报一个瑜伽班。

2.Henry brought this on himself, Dawn.
Henry这是咎由自取。

bring on
引起不好的事情；使不好的事情发生

You have brought disaster on the whole village!
你给整个村带来了灾难！

3.Before someone else catches on to us.
在别人发现之前。

catch on
变得流行；曝露

The idea of glasses being a fashion item has been slow to catch on.
眼镜慢慢变得流行起来。

4.So I could fill in for her.
所以我可以暂时代替她。

fill in for sb.
暂时代替某人

I'm filling in for Joe for a few days.
这顿时间我会代替Joe。

5.But I have never decorated a school dance before, much less attended.
但我以前从未布置过校园舞会，更别说参加了。

much less
更不用说；何况

The shelves were lined with books which neither Hugo nor Sally would ever open, much less read.
那个书架Hugo和Sally从来就没打开过，更不用说看过里面的书了。

6.What would you say if I told you that Dawn and I were seeing each other?
如果我告诉你我和Dawn在一起了，你会怎么想？

be seeing somebody
和某人约会

Is she seeing anyone at the moment?
她是不是在和某人约会？

7.I was just roping some people into helping Sally with dance committee stuff.
我只是找了一些人来帮Sally处理舞会筹办会的事情。

rope someday into something/doing
说服某人参加...

Denise roped me into selling tickets.
Denise找我帮忙一起售票。