idioms 习语
couch potato 老泡在电视机前的人
Sheldon used to play basketball and hockey, but lately he has been a bit of a cough potato.
a bolt from the blue意外事件
Sometimes, the thing that gets you through hard times comes like a bolt from the blue. That's waht my older brither's letter was like , traveling across the country from a work camp in Wyomping.
get the green light 得到允许
grin and bear it 逆来顺受
like there was no tomorrow 不计后果/尽情地
a penny for your thoughts （用以询问）你在想什么呢
cost an arm and a leg 极其昂贵
cry over spilt milk 后悔无及/覆水难收
cut the mustard 符合要求
Don’t put all your eggs in one basket. 不要孤注一掷。
make a long story short 长话短说/简言之
relative pronouns 关系代词
Relative pronouns are a type of subordinating conjunction. Relative pronouns introduce relative clauses. Relative clauses are a type of dependent clause. 关系代词属于一种从属连词，它引导定语从句。定语从句是一种从属从句。
Rule 1: relative pronoun (as subject) + predicate
Rule 2: relative pronoun + subject + predicate
Relative adverb: where, when ,why
