said he ___ (buy) a book yestoday以及原因

的确 一楼说的很正确 about to 表示很快 very soon 不过一楼犯了一个小错误 be about to + 动词原形
看到它的英文解释的最后 if someone is about to do sth,of if sth is about to happen,they will do it or it will happen very soon
例句如下
We were just about to leave when Jerry arrived.
Jerry来时我们刚想走
Work was about to start on a new factory building.
工作很快会在一栋新厂房开始
不过我们还注意到 about to 还有一层含义就是按计划
但是be going to 在表示将来时 不仅仅包含一种打算 或者计划 还包含了未来会发生的事情（客观发生的）所以A是正确的

保证答案准确率!1.Come here2.Don't play3.Let's 或 Please（祈使句句尾应该是句号或叹号,不是问号吧）如果是问号,则答案肯定不止一空,可以是：Why don't we 或 Why not4.Let's5.Hurry up如果你满意我的答案,敬请点...

used to 被用来
refer to 参考；涉及；指的是；适用于
翻了下英英词典,
这句话的意思就是说：this这一词通常被用来指代当前事件、行动或时间
它举了个例子：he'd be back before this.这个this在这里就是代指“时间”,意为“他将会在这之前回来
he'd是he would的缩写,“他将会”,表示他说的一种将来时态

He asked me to make sure the door was shut.

B

不定代词something和everything有一个特别的含义；something重要事物，重要人物；everything最重要事物，最重要人物。

He said that he was glad to receive my e-mail.

Children often have far more sense than their elders.This simple truth was demonstrated rather dramatically during a civil defence exercise in a small town in Canada.Most of the inhabitants were asked to take part in the exercise during which they had to pretend that their city had been bombed.Air-raid warnings were sounded and thousands of people went into special air-raid shelters.Doctors and nurses remained above ground while Police patrolled the streets in case anyone tried to leave the shelters too soon.The police did not have much to do because the citizens took the exercise seriously.They stayed underground for twenty minutes and waited for the siren to sound again.On leaving the air-raid shelters,they saw that doctors and nurses were busy.A great many people had volunteered to act as casualties.Theatrical make-up and artificial blood had been used to make the injuries look realistic.A lot of People were lying 'dead' in the streets.The living helped to carry the dead and wounded to special stations.A Child of six was brought in by two adults.The child was supposed to be dead.With theatrical make-up on his face,he looked as if he had died of shock.Some people were so moved by the sight that they began to cry.However,the child suddenly sat up and a doctor asked him to comment on his death.The child looked around for a moment and said,'I think they're all crazy!'

答案是：

第一句已经有朋友帮你回答了,我来回答你的追问
he asked me if I was going home that weekend

~手工翻译,尊重劳动,欢迎提问,感谢采纳~

he said that he was very glad to receive your e-mail

He said that make sure the door was shut

he said he was glad to receive my email.(that 可省略）