1.This school is [ mainly ] ( main ) for boys ; there are only a few girls in it .
翻译:这所学校主要招收男生,只有几个女生.
mainly 是副词,修饰短语 for boys
2.It isn't worth [ waiting ] ( wait ) for him .
翻译:不值得等他
be worth doing 固定搭配
3.I left there [ secretly ]( secret ) yesterday .
翻译:我昨天悄悄离开了那里
secretly 副词修饰动词 left
4.What is your [ preference ] ( prefer )
翻译:你喜欢什么
preference 名词做your 的宾语
5.Edison [ was born ] ( bear ) in Ohio in 1847 .
翻译:爱迪生于1847年生于俄亥俄州
be born in 生于.