重点难点：
1. What should you do if a person has drunk poison by mistake? 假如有人误喝了毒药，你怎么办?
by mistake是固定词组，意为“错误地”，“无心地(做错了事)”。例如：
She put salt in her cup of coffee by mistake.她错将盐放入咖啡里了。
2. do with，deal with
二者都可以用来表示“处理”的意思
但是用于特殊疑问句的时候do with与what连用;deal with则与how连用。例如：你会怎样处理一个从自行车上摔倒而严重受伤的?
另外，do with还可表达别的意思。例如：
What did you do with my umbrella? (=Where did you put my umbrella?)
你把我的伞放到哪里去了?
What are we to do with this naughty boy? (=How are we to deal with this naughty boy?) 我们该怎样处置这个顽皮的男孩?
3. knock at, knock down & knock into的区别
knock at 指“敲打门窗”
I heard someone knocking at the door.我听见有人敲门。
Tom tried knocking at the window.汤姆试着敲了敲窗户。
knock down 指“……撞倒”
He nearly knocked me down at the corner.在拐角处，他几乎把我撞倒。
He was knocked down by a car. 他被汽车撞倒了。
knock into 指“碰倒，撞上某人”，也可指“偶然碰见”。
The child knocked into the teacher.那孩子撞到了老师身上。
He knocked into the chair in the dark.黑暗中他撞在了椅子上。
He didn't expect to knock into some of his friends here.他没有想到在这儿遇见一些朋友。
4. ask, demand, inquire, question & require
1)ask是一个常用词，表示“问”的意思。
Did you ask the price of that ten-speed bicycle?你打听过那辆十速自行车的价钱了吗?
2)demand含有强硬、断然的意味。
I demand that you leave this place at once.我要求你立即离开此地。
3)inquire 多用于较正式的语体，通常只表示打听消息，寻求答案。
He inquired of the girl the way to the railway station.他问那女孩到火车站怎么走。
4)question 常表示一连串问题，有时则有盘问，审问之意。
①The questioning of the prisoner went on for hours.对那个囚犯的审讯延续了好几个小时。
5)require有按照权利来“要求”或“命令”之意。
Since he was involved in the case, the court required his appearance.由于他与此案有关，法庭令他出庭。
