英语语法高手进
1. 正确。
2. 你说的对，主语是how many people.
3. long before 是一个连词，和before 的用法是一样的，引导一个时间状语从句，后面不能再加and了。
mean
及物动词 vt.
1.(言词等)表示...的意思[+(that)] eg: What does the phrase mean?
2.意指,意谓[+(that)][+wh-] eg: Don't think I am joking; I mean business.
3.意欲,意图,打算[+to-v][O1][O2] eg:I mean her no harm.
4.意谓着;有...的意义[+(that)][+v-ing][(+to)]
To a certain extent, to raise wages means increasing purchasing power.
5.指定;预定[H][(+for)][+to-v] eg:The apartment was originally meant for five.
不及物动词 vi. [W] 用意
形容词
1.中间的,中等的,中庸的
2.平均的;普通的 eg：What is the mean temperature in that locality? 那个地方的平均气温是多少?
词组：
1.by all means 尽一切办法，务必
2.by any means 无论如何
3.by means of 用，凭借
4.by no means 决不，并没有
5.mean business 是认真的
guess
及物动词 vt.
1.猜测;推测[+(that)][+wh-] eg: I can guess what will happen next.
2.猜中,猜对 eg:I guessed his thoughts.
3.【美】【口】想,认为[W][Y][+(that)] eg:I guess we'll have to wait a few more minutes.
不及物动词 vi.
1.猜;推测[(+at/about)] eg:We can only guess at the result.
2.猜中
3.想,认为
名词 n.
1.猜测;推测[C] eg:My guess is that it will rain tomorrow.
关系代词who与whom 的用法区别 两者均只用于人，从理论上说，who 为主格，whom为宾格。如：Where’s the girl who sells the tickets? 卖票的女孩在哪里？ The author whom you criticized in your view has written a letter in reply. 你在评论中批评的那个作者已写了一封回信。但实际上，除非在正式文体中，宾格关系代词 whom 往往省略不用，或用who或that代之。如：The man (that, who, whom) you met just now is called Jim. 你刚遇见的那个人叫吉姆。 不过，在以下几种情况值得注意。如：(1) 直接跟在介词后面作宾语时，只能用 whom，而且不能省略。如：She brought with her three friends, none of whom I had ever met before. 她带了brought with her three friends, none of whom I had ever met before. 3个朋友来，我以前都没见过。(2) 引导非限制性定语从句且作宾语时，who 和 whom均可用，但以用 whom 为佳，此时也不能省略。如：This is Jack, who [whom] you haven’t met before. 这是杰克，你以前没见过。
will与would的用法
表示意志或意愿：决心，愿意，……好吗？
We will do our best to save the child. 我们会尽力抢救这个孩子。
I told her to stop crying, but she just wouldn’t listen. 我叫她别哭,可她就是不愿听。
注：表示请求、建议或征求对方意见时，用Would you…? 比用Will you…?更婉转。如： Will/Would you please keep the door open?请让门开着好吗？
Will/Would you go with me?你愿意和我一起去吗?
表示真理或习惯：惯于，总是
Oil will float on water. 没总是浮在水面上。
She will listen to music alone in her room for hours. 他独自在房间里听音乐，一听往往就是几小时。
He would get up early when he lived in the country. 他住在乡下时总是早起。
表示要求：一定，必须
You will report to me afterward. 你稍后一定要向我报告。
表示猜测：可能，大概
his will be the house you’re looking for. 这大概就是你找的那所房子了。
I think he would accept the invitation. 我想他会接受邀请的。
表示功能：
This auditorium will/would seat one thousand people. 这个礼堂能容纳一千人。
would like表示愿意
I would like to have a word with you. 我想同你说句话。
Would you like a cup of tea? 请你喝杯茶好吗？
would rather…than…宁愿……也不愿……
I would rather fail than cheat in the examination. 我宁愿考不及格，也不愿意考试作弊。
would与used to的比较
(1) 两者都可以表示过去经常做某事，常可互换。如：
When I was young I used to/would get up early. 我年青时经常早起。
(2) 下列三种情况要用used to，不用would：
◇强调与现在的对比时；
◇在故事开头时；
◇与be, stay, belong, live, like , think, know等状态动词连用时。如：
He doesn’t work hard as he used to. 他不像以前那样努力了。
We used to swim every day when we were children. We would run down to the lake and jump in…我们小时候天天游泳。我们会跑到湖边，跳进水里……
They used to live here, didn’t they? 他们以前住在这里，是不是？
(3) 与时间段或与表示“有时”意义的sometimes, at times, now and then, from time to time等连用时，宜用would。如：
He would sit like that for hours. 他会像那样一坐就是几个钟。
Sometimes the boys would play a trick on the teacher. 有时孩子们会戏弄老师。
(对)That is my teacher. 那是我的老师。（ that作主语，指人）
(对)He is going to marry this girl. 他要和这个姑娘结婚。（this作限定词）
(错)He is going to marry this. （this作宾语时不能指人）
(对)I bought this. 我买这个。(this指物，可作宾语)
说明2：
That和those可作定语从句的先行词，但this和 these不能，同时，在作先行词时，只有those可指人，试比较：
(对) He admired that which looked beautiful. 他赞赏外表漂亮的东西。
(对) He admired those who looked beautiful. 他赞赏那些外表漂亮的人。（those指人）
(错) He admired that who danced well. （that作宾语时不能指人）
(对) He admired those who danced well. 他赞赏跳舞好的人。（those指人）
(对) He admired those which looked beautiful. 他赞赏那些外表漂亮的东西。（those指物）
that 可以指人和物
1.these those this that 做宾语时一般都不会指人，当要直人时 如I love these（those, this, that) people. 这里他们做people的前置定语来修饰people. this that those these 这四个词在语法上除单复数外没什么特别的区别点this(these)这（些）that(those)那（些）
2. 在定语从句中指人一般用who或whom. 但并不是that就不能指人。如He is the teacher that(whom) I always mention.
