第一问：
indoor 是一个形容词 i户内的,室内的
* Snooker is an indoor sport.
* The high percentage of death and disease is linked to indoor air pollution.
indoors - 是一个副词 在室内,在户内
* You should stay indoors if you are not well.
* Come indoors,it's cold outside.
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做对第二题 关键是要记住后边的接续成分是什么,不要只记住意思
游泳爱好者每天坚持游泳,甚至在寒冷的冬天.
in cold winter 是一个短语,不是句子 要用even
even if 引导条件状语从句 后边接句子
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1.Even 可用于加强语气用,作甚至,连的意思解; 也可以用于比较级前,作甚至更,还的意思解.
Even 作"甚至" 解时,通常置于所修饰的字的前面,修饰动词时,如有肋动词则置于助动词之后
Even a child can answer such an easy question.这么简单的问题连小孩子也会回答.
He couldn't even answer such an easy question.他连这么简单的问题也回答不出
2.Even if 常用于引导状语从句
It seems to be your fault,even if the teacher would claim to be responsible for the loss.似乎是你的错,尽管这位老师愿意为由此造成的损失承担责任.
You shouldn't look a gift horse in the mouth,even if such a pen is not very expensive.你不该拿了人家的东西还挑剔,尽管这样一支笔不是很昂贵的.
I hate you even if you're my father.我恨你,即使你是我的父亲.
Even if we could have taken a vacation,we might not have wanted to.即使我们能够休假,我们也许也不需要.