1、1、even if（=even though 即便）请比较下面两个例句：You must go tomorrow if you are ready 如果你准备好了，明天你必须走。You must go tomorrow even if you arent ready 哪怕你没有准备好，明天你也得走。2、 whetheror（=if or 是否）You must go tomorrow whether you are ready or not无论你明天是否准备好了，你都必须走。3、unless肯定动词（if否定动词除非）Unless you start at once youll be late
2、相当于：If you dont start at once youll be late 除非你立即动身，否则你就会迟到。Unless you had a permit you couldnt get a job相当于：If you hadnt a permit you couldnt get a job除非你有执照，否则你就找不到工作。注意下面两个例句间的区别：（a） Dont call me if you need help 如果你需要帮助的话，别打电话找我。（b） Dont call me unless you need help 除非你需要帮助否则别打电话找我。在例句（a）中，即使在对方
3、需要帮助的时候，说话人也不愿意去帮助对方。在例句（b）中，在对方需要帮助的时候，说话人愿意帮助对方，但说话人不愿意对方在不要紧的时候打电话找自己。unlesshe dyoud likeprefer 等通常可用来代替 if heyou wouldnt like 等：Ill ask Tom，unless youd prefer me to askunless you d rather I asked Bill 我去问汤姆，除非你宁愿叫我去问比尔。4、but for（=if it were not forif it hadnt been for 不然）My father pays me feesBu
4、t for that I wouldnt be here 我父亲给我一笔补贴费。不然我就不会在这里了。The car broke down But for that we would have been in time汽车出毛病了。要不是那个我们会及时赶到的。5、 otherwise（=if this doesnt happendidnt happenhadnt happened 否则）We must be back before midnight； otherwise well be locked out 我们必须在午夜之前赶回去，否则我们就会被锁在门外。相当于：If we are not
5、back by midnight well be locked out如果我们不在午夜之前赶回去，我们就会被锁在门外。Her father pays her fees；otherwise she wouldnt be here 她的费用是她的父亲付的，否则她就不会在这里。相当于：If her father didnt pay her fees she wouldnt be here要是她的父亲不付她的费用，她就不会在这里了。I used my calculator； otherwise Id have taken longer 我用了计算器，不然我花的时间就会更多。相当于：If I hadnt
6、 used my calculator Id have taken longer 要是我没用计算器，我花的时间就会更多。6、在日常英语中 or（else）可以代替 otherwise：We must be early or（else ） we wont get a seat我们必须早去，否则就不会有座位了。7、存在强烈的限制或约束的意思时，provided （ that）可以代替 if。它主要用来表示允许：You can camp here provided you leave no mess 你们如果保持整洁的话，可以在这里宿营。H supposesupposing？（=what if？假如
7、）Suppose the plane is late？相当于：What ifWhat will happen if the plane is late？假如飞机误点的话，将会出现什么情况？Suppose no one had been there？相当于：What if no one had been there？假如没有人去过那里的话，会怎么样？suppose 也可以引出建议：Suppose you ask him？Why dont you ask him？ 假如你问一问他呢？你为什么不问一问他呢？worth、worthy、worthwhile 的用法区别这三个词都是形容词，都有“值得的”的
8、意思，但用法或搭配关系不同。1. worth 是一个只能作表语的形容词，意思为“值的”、“相当于的价值的”、“有 价值的”、“值得 的”。后接名词、接动名词的主动形式。例如：This second-hand car is worth $2000 at the most.The exhibition is worth a visit/visiting.Its not worth getting angry with him.The question is not worth discussing again and again.2. worthy 可作表语，也可作定语。作定语时意思为“有价值的”
9、、“值得尊敬的”、“应受到赏识的” ；用作表语时意思为“值得的” 、“应得到的”，其后接 of sth.，也可以后接 to do sth.，例如：That is worthy of note. 那件事值得注意。This phenomenon is worthy of being studied. 这种现象值得研究。This problem is worthy to be considered. 这个问题值得考虑。The film is worthy to be seen again. 这部电影值得再看一遍。This is a worthy English-Chinese dictionary.
10、 这是一本有价值的英汉词典。This is a worthy article. 这是一篇值得一看的文章。He said he was not worthy to accept such honourThe school has educated many worthy young people.The question is not worthy to be discussed again and again.作后置定语时，必须用“worthy of +名词”结构。例如：There is nothing worthy of mention. 没有值得一提的事情。This is behavior
11、 worthy of praise. 这是值得称赞的行为。 Something find and rare - something worthy of the honor of being owned by Jim. (S3 Unit 10 P84)注：“worthy of+动名词” 与“worth+动名词”在形式上完全不同：worthy of 后面接被动式的动名词；而 worth 后面接主动式的动名词，虽然在形式上是主动的，但其意义仍然是被动的。试比较：The second-hand house is worthy of being bought. = The second-hand hou
12、se is worth buying.3. worthwhile 与 worthy 一样，既可作表语，又可作定语。表示某事因重要、有趣或受益大而值得花时间、金钱或努力去做，一般做“值得的”、“值得做的”、“有意义的” 解。用作表语时，可接动名词或动词不定式。例如：The Summer Palace is worthwhile going / to go to have a visit.Helping old people is a worthwhile activity.Thank you for your worthwhile suggestion.I really feel I am do
13、ing something worthwhile and I am having a great time doing it.一句多译：The place is worth a visit. The place is worthy of a visit. The place is worth visiting. It is worth visiting the place. The place is worthy of being visited. The place is worthy to be visited. It is worthwhile visiting the place. It is worthwhile to visit the place.
