高二英语教材知识点总结及重难点解析Unit19-20
(4) on + 动名词 (或表示动作的名词)归纳：动名词(或名词)结构表示它所表达的动作刚一发生或完成，句子谓语所表示的动作就接着发生。它相当于as soon as 引导的时间状语从句。on arriving in england, they were taken to the crystal palace by train. 他们一到英国便乘火车去水晶宫。he was greeted by the prime minister on his arrival at the airport. 他一到机场，便受到总理的欢迎。
另外，each time，every time 如同上面四种类型一样，可直接用作从属连词，引导状语从句。every time i listen to his advice, i get into trouble. 我每次听了他的劝告，都会遇到麻烦。i'll think of my hometown each time i listen to that song. 我每次听这首歌，都会想起家乡。
3. as...as... 与比较级的用法
(1) ...as + 形容词(副词)原级 + as...；not as / so + 形容词 (副词) 原级 + as... i study as hard as you. 我学习和你一样努力。he doesn't get up as / so early as his parents.他起床没有他父母亲早。
(2)……倍数 + as + 形容词(副词)原级 + as... line ab is 3 times as long as line cd. = line ab is twice longer than / 3 times the length of line cd. 线段ab是线段cd的三倍长。
(3) as + 形容词 + a / an + 单数可数名词 + as；as + 形容词 + 复数名词 + as i haven't got as much money as i thought. 我的钱没有我想像的那么多。
(4) as much / many as 多达……，……那么多this factory produces as much as 100 tons of steel a day. 这家工厂每天产铁 100 吨。as many as 700 different languages are spoken in africa. 在非洲人们所说的语言多达700多种。
5. x times + n. 通过结构，应掌握英语里表示倍数的表达句型。
a is x times the size (height, length, width...) of b.
a is x times as big (high, long, wide...) as b.
a is x times + adj.-er than b.
the size (height, length, width...) of a is x times that of b.
the meeting-room is three times the size of our office. = the size of the meeting-room is three times that of our office.
三倍以下通常用double或者twice来表达两倍。his weight is double what it was ten years ago. / this railway is twice longer than that one. / the room is twice the size of that one. = this room is twice as big as that one.
☆句型归纳☆
【考点1】as far as i know... 据我所知……
as far as是连词，本意为“和……一样远”。引申意为“就 ……(程度，范围) 而言，至于，尽……”。类似的还有：as long as“和……一样长”。“只要”；as good as“和……一样好”。“实际上，事实上，和……几乎一样”；as well as “和……一样好”，“既……又……，不但……而且……”。例如：as far as i know, he isn't coming to the party. 就我所知，他不会来参加这次聚会。as far as he is concerned, he can't afford such an expensive car. 就他而青，他买不起这么贵的汽车。
【考例1】(北京、安徽) ____ i can see, there is only one possible way to keep away from the danger.
