every, each 和 each of 后面用单数还是复数
every 总是修饰单数名词，后接单数动词。
each 作为形容词，修饰单数名词，接单数动词。
- 作为代词，单独使用，接单数动词；
- 放在复数名词和复数代词后作同位语，接复数动词。
each of + 名词复数作主语，后面的谓语动词用单数。
例句：
1, They call rowing the perfect sport. It exercises every major muscle group.
他们称划船是最佳运动，它可以锻炼每一处主要肌肉群。
2, You don't have to go running upstairs every time she rings.
用不着她一来电话你就往楼上跑。
3, After sixteen years of marriage they have grown bored with each other.
结婚 16 年后，他们已经渐渐彼此厌倦了。
TIP
- grown 渐渐变得
4, Each family farms individually and reaps the benefit of its labor.
各家经营各自的农场，收获各自的劳动成果。
5, Each of these exercises takes one or two minutes to do.
这些练习题每道要花一两分钟。