Life isn't all fun; it has its bad moments 这句话后面那个 moment为什么

It isn't worth it 中为什么后面要加it?而不是It isn't worth isn't it great fun?英语翻译 isn't life 和isn't life...还有isn't it. isn't life 和isn't life...什么意思,还有isn't it. -Isn't this your hangbag -Yes,it is./No,it isn't.这句话怎么翻译? Nor is the city without its moments of beauty.这句话里能不能这么写,the It's fun（ ）volleyball on the beach,isn't Life has its ups and downs, but it certainly has its rewards isn't it beautiful?和is it not beautiful?那个是正确的?为什么? Lovely day,isn't it?这句话怎么回答? what a fine day,isn’t it?这句话对吗 it has为什么外国人发音是its