2014年9月19日,iphone6正式上市。随着iphone系列的热卖,带动了苹果手机膜、手机壳等配套产品的生产。这主要体现了( )
—________do you communicate with your friends far away? —By sending e-mails.
It’s a lovely day.What about________for a picnic?
In school,we often learn English by working________a group.
The students raise money for their school trip________newspapers.
You won’t feel happy at school________you get on well with your classmates.