Notes on the text
1. This platform would serve as a port and a railway station. 这座平台将用作码头和火车站。
serve as: 用作……,充当……
2. In 1860,a better plan was put forward by an Englishman, William Low. 1860年，一位名叫威廉·洛的英国人提出了一项更好的计划。
put forward: 提出
3. This would solve the problem of ventilation,for if a train entered this tunnel,it would draw in fresh air behind it. 这样就解决了通风问题。因为如果有一列火车开进隧道，它就把新鲜空气随之抽进了隧道。
for在句中引导的是原因状语从句
draw in: 吸进，抽入
4. If,at the time,the British had not feared invasion,it would have been completed. 如果不是因为那是英国人害怕入侵，隧道早已建成。
此句为if引导的非真实条件句，与过去事实相反。从句要用过去完成时(have not feared)，主句用would+have done(would have been)
Key structures
if引导的真实条件句：主句用将来时（will+do），从句用一般现在时，即主将从现。
例句：If he is out, I"ll call tomorrow.
if引导的非真实条件句
1. 与现在、将来事实相反的假设：主句用would+do,从句用过去时（be动词统一使用were）。
例句：If I were you, I would go at once.
If you went to the exhibition,you would enjoy it.
2. 与过去事实相反的假设：主句用would+have done,从句用过去完成时（had done）
例句：If I had been in your position,I would have acted differentlly.
Special difficulties
draw相关短语的不同用法
1. draw in: 吸入 If a train entered this tunnel,it would draw in fresh air behind it.
2. draw back: 后退 The dog drew back in terror when it saw the snake.
3. draw up: 停车 A taxi drew up outside the bank.
签署 A new trading agreement was drawn up between Holland and Denmark.
附 本课单词听写表
