条件状语从句
条件状语从句就是在复合句中表示主句动作发生条件的状语从句。
1. 用if引导：if意为“如果”。如：
You can’t take photographs if the light is bad.
主将从现
If the problem is overlooked, it is likely to deteriorate.
2. 用unless引导：unless的意思是“如果不”“除非”。
Unless you go at once you will be late.
除非费用是合理的，不然博物馆收费将会打击到游客的热情。(dampen the passion) charge
Unless the price is reasonable, or / otherwise, charging by the museum dampens the passion of visitors.
3. 用as [so] long as引导：as [so] long as的意思是“如果”“只要”。
You may take my dictionary as long as you don’t keep it too long.
As long as you love me
4. 用in case引导：in case用连词引导条件状语从句时，其意为“如果”“万一”。
In case I forget, please remind me about it.
Sth remind sb of sth
This song reminds me of my childhood.
5. 条件状语从句的时态：当主句为将来时态或含有将来意义时，条件状语从句习惯上要用一般现在时表示将来意义，而不能直接使用将来时态。如：
不知道明天是否会下雨，但要是下雨的话，我就呆在家里。
I don’t know if it will rain tomorrow. But if it rains tomorrow, I’ll stay at home.
让步状语从句
让步状语——这是一个比较奇怪的名字。所谓让步，简单地说就是降低标准或者说是退一步，相当于汉语的“虽然”“尽管”“即使”等。
1. 用although / though引导：although与though虽然拼写不同，但意思相同，都表示“虽然”，常可互换。如：
despite / in spite of
Though they are twins, they look entirely different.
注意，不要按汉语习惯说although…but…。
2. 用even though / even if引导：even though和even if意思相同，均表示“即使”，常可互换。如：
Even though you have a lot of money, I won’t love you.
The government should make higher education free for all students regardless of their financial background. Do you agree or disagree?
即使政府拨款，每个学校获得的资金是很有限的。免费的大学教育，有可能最终降低了教学质量。
Even though the government allocates the budget, the fund received by every university is limited. Free higher education is likely to decline the teaching quality ultimately.
Even though governmental budget will be granted, universities are underfunded.
3. 用whether…or引导：whether…or…的意思是“无论……还是……”“不管……还是……”。如：
I’ll do it whether you like it or not. 不管你是否喜欢，我都要做。
4. 用特殊词引导：除上面提到的最常用的引导让步状语从句的词语外，有时还可用那些以-ever结尾的词语来引导，如whatever, whoever, however, whenever, wherever等，它们的意思与no matter what, no matter who, no matter how, no matter when, no matter where等，意思是“无论什么”“无论是谁”“无论多么”“无论什么时候”“无论什么地方”等。如：
Whatever you say, I believe you. 无论你说什么，我都相信你。
Whoever telephones, tell them I’m out. 不管是谁打电话，都说我出去了。
However much he eats, he never gets fat. 无论他吃多少，他都不发胖。
另外，还有一个大家比较熟悉的词也可引导让步状语从句，那就是while，它除了表示“当……时候”外，还可表示“尽管”“虽然”，此时引导的是让步状语从句。如：
While we don’t agree we continue to be friends. 尽管我们意见不同，我们还是朋友。
