Are you going to the movies tonight?今晚去看电影,为什么要用going?

　　因为be going to 是表将来要发生啊!
　　each of ...是单数形式 重心在each,each 作为一个数量词

如：Each of these exercises takes one or two minutes to do.每一道题都得花一或两分钟时间来做.

　　sb each 的重心是sb,each 强调,有同位语的意味

如：we each have different background,我们每个人都拥有不同的背景.(我们)