1..You aren't a stranger,are you 你不是一个陌生人,是吗?
肯定回答,我是一个陌生人.yes,i am.
否定回答,我不是一个陌生人.no,i am not.
记住,回答反义疑问句,按实际情况回答,和怎么问的没关系.
变式：you are a stranger,aren't you
回答也是一样的,按实际情况回答.
肯定回答,我是一个陌生人.yes,i am.
否定回答,我不是一个陌生人.no,i am not.
2..why not do sth,why don't you do sth
例句why not go for a movie?why don't you go for a movie?
3.contribution to ding .to是介词,后跟动名词.
拓展：contribute to sth.=contribute to dong.=make a contribution to sth.=make a contribution to dong
4.speaking是主动的,动名词兼现在分词.spoken是被动的,过去分词.
典例：Speaking English is very important.( 动名词做主语）
Native speakers speaking English know the saying( 谚语)well.(现在分词人作主语）
English spoken in Canada is quite different from that spoken in America.(过去分词物作主语）
累死我了 我确定我说的是对的.