1.if作“是否”讲的时候,与whether同义,都可引导宾语从句,可以互换 2.口语中常用IF,但是从句中有OR NOT 的时候,则只能是用WHEATHER,例如:I don‘t know whether it’s raining or not. 3.另外,WHETHER可以引导主语从句,表与从句,同位语从句,IF 则不能,IF(意为“如果“)可以引导条件状语从句,WETHER则不能,WETHER可以和不定式连用,IF 则不能。He doesn‘t know whether to accept the invitation. 4.WHETHER引导的宾语从句可以放在介词后面,IF引导的宾语从句则不能。例如: It depends on whether he is coming。
一、DCDCBBCDAADCBCA二、 1. Clare. 2. For two years. 3. Because Peter works in the company and ithas offices in many countries. 4.Five. 5. Because their family willmove back to the US. 三、。 1. D 2. C 3. E 4. B 四、 1. has been tomany interesting places 2. I have learntto speak 3. is different fromEnglish 4. is one of thebiggest and busiest 5. You’d better stop traveling