They both play soccer，don't they？
Ther‘re both going to the concert？
为什么第一个没有be动词?而第二句有
They both play soccer，don't they？
句子语法结构分析如下
主语：They（他们）
同位语：both（两个）
谓语：play （行为动词做句子简单谓语）（踢）
宾语：soccer (英式足球拼写法）
both 作主语的同位语，他们两个都踢足球
Ther‘re both going to the concert？
句子语法结构分析如下
主语：They（他们）
同位语：both （两个）
谓语：is going （助动词+行为动词现在分词构成句子复合谓语）
状语：to the concert （去听音乐会）
BOTH 放在BE 动词之后，行为动词之前，他们两个都要去听音乐会
为什么第一个没有be动词?而第二句有
【第一句的句子结构为：主语+谓语+宾语 结构， 句子谓语由行为动词play充当】
【第二句的句子结构为：主语+谓语+状语结构， 助动词is +行为动词现在分词构成句子复合谓语，也就是现在进行时态，不过这里是现在进行时态表示将来的意义
】
（备注：请务必记住BOTH 做同位语在句子放置位置：BE 动词之后 ；行为动词之前）
例如：They both want to go there （both在行为动词 want的前面）
例如：They are both good students (both 在系动词are 的后面）
答题不容易，如果满意，请及时采纳，谢谢！
both形容词 adj.
1.二者, 两者都
代词 pron.
1.二者
副词 adv.
1.二者, 二者都
连接词 conj.
不仅…而且…；…和…都
adj. 二者，两者都
pron. 二者
adv. 二者，二者都
conj. 不仅…而且
两个；两个都 You use both when you are referring to two people or things and saying that something is true about each of them.
She cried out in fear and flung both arms up to protect her face...
她吓得大叫，并且抡起双臂护住了自己的脸。
Put both vegetables into a bowl and crush with a potato masher.
把这两样蔬菜都放进一个碗里，然后用捣土豆器把它们捣碎。
Both is also a quantifier.
Both of these women have strong memories of the Vietnam War...
这两位妇女都对越南战争记忆深刻。
We're going to Andreas's Boutique to pick out something original for both of us.
我们要去安德烈亚斯礼品店为我们俩挑选一些新奇玩意儿。
Both is also a pronoun.
Miss Brown and her friend, both from Stoke, were arrested on the 8th of June...
布朗小姐和她的朋友于6月8日被逮捕，她们两人都来自斯托克。
Will there be public-works programmes, or community service, or both?
将会实施公共工程项目还是社区服务项目，还是二者都有？
Both is also an emphasizing pronoun.
He visited the Institute of Neurology in Havana where they both worked...
他访问了两人都曾工作过的哈瓦那的神经病学研究所。
'Well, I'll leave you both, then,' said Gregory.
“好吧，那我就不打扰你们俩了。”格雷戈里说道。
Both is also a predeterminer.
Both the band's writers are fascinating lyricists...
乐队的这两位作词人都是非常出色的填词高手。
Both the horses were out, tacked up and ready to ride. 两匹马都牵出来装上了马具，可以骑了。
不仅…而且…；…和…都；既…又… You use the structure both...and when you are giving two facts or alternatives and emphasizing that each of them is true or possible.
Now women work both before and after having their children...
现在妇女在生孩子前后都要去工作。
Any such action would have to be approved by both American and Saudi leaders.
任何这样的行动都必须获得美国和沙特领导人双方的批准。
注意以下各句含义相同：
Both boys have been ill, Both the boys have been ill, Both of the boys have been ill, The boys have both been ill（两个男孩都病了）。不能用 Both of boys have been ill，但在和代词一起使用时可以说 Both of them have been ill（他们两个都病了）。亦见all词条下的说明。
1.He charged at me with his head down and both fists flying.
他低着头，挥舞双拳朝我冲来。
2. When we use "he", we generalize for both sex.
当我们用he时，我们泛指男女。
3. He held both sides of the parka hood closed against the snow.
他捏紧皮外套上风帽的两边以挡住袭来的飞雪。
4. The captain cares the safety of both the crew and the passengers.
船长为船员和旅客们的安全操心。
5. Bill is both a good swimmer and a good cook.
比尔不仅是个游泳好手，而且是个烹调能手。
6. Mental and physical deterioration both occur naturally with age.
随着年龄的增长，心智和体力自然衰退。
7. These habits are both universal among mankind and peculiar to individuals.
这些习惯在全人类中很普遍，而对个人来说又很独特。
8. Both the twin brothers were born and bred in London.
这对双胞胎兄弟是在伦敦长大的。
9. This is a ruler graduated in both inches and centimetres.
这是一把刻有英寸和厘米的尺子。
10. Agency France Presse enjoys great popularity both at home and abroad.
法新社在国内外都很有名气。
11. She and I both arrived at the same time by pure coincidence.
我和她同时到达纯属巧合。
12. With the blind leading the blind, both shall fall into the ditch.
如果瞎子替瞎子带路的话，那么两方肯定会掉到沟里。
13. Line the pages for the graph both horizontally and vertically.
在这几页上同时画上横线和竖线，以便制作图表。
14. He scored out both calculations and did them again.
他把两个计算结果都划掉，又把它们计算了一遍。
15. The proposal offered both sides a way out of the diplomatic impasse.
这一提议使双方都能摆脱外交僵局。
16. The uproar was enough to rouse both the quick and the dead.
这喧嚣声足以惊醒生者和死者。
17. There is much to be said for both sides of this question.
这个问题正反两方都能讲出许多道理来。
18. The process is essentially dynamic with ideas and feedback flowing both ways.
这个过程本质上是动态的，有各种建议与反馈的双向交流。
19. Are you able to keep both the gardeners on?
你还能继续雇用这两名花匠吗？
20. The moves contravene the peace plan agreed by both sides.
这些举措违反了双方同意的和平方案。
Both his eyes were severely burned.
他的双眼都严重烧伤了。
代词pron.
两者;两个Why not buy both? 为什么不把两件都买下？ 副词ad. 1.并；又；两者皆 We like Amy and Phil both. 艾米和菲尔两个我们都喜欢。 连接词conj. 1.既。..且。..;...和。..都 The prospects bothexcited and worried me. 这前景即使我激动又令我忧虑。
might be和might又有什么区别呢？It might mean “worried” The earrings might be a present for his mother？第一个为什么没有加be
追答might是情态动词，意思是“可能”，其后跟动词原形
might be 后面加的那个 be 只是刚好后面的句子要用到be动词，而跟在情态动词后只能使用动词原形，所以涉及到be动词都统一使用 be ，翻译为 “可能是” ，比如
He might buy that book 他可能会买那本书。
This book might be his . 这本书可能是他的。