英语知识用if/whether连接宾从一、DoyouknowCanhecomehereontime?二、Canyoutellme?Whocanrunfastestinclass?三、CanyoutellmeWhatistheadvantageofwesternfastfood?四、Doyouknow?Isitpolitetoeatupthefoodon

Question

英语知识
用if/whether连接宾从 一、Do you know Can he come here on time?二、 Can you tell me?Who can runfastest in class?三、 Can you tell me What is the advantage of western fast food?四、Do you know?Is it polite to eat up the food on your plate?

Answer 1

一、if或whether引导宾语从句时,作“是否”讲,常放在动词ask 、see 、say 、know和find out等后面.一般情况下,两者常可换用,在口语中多用if.如：
二、if或whether引导宾语从句时,要注意三个方面,即连词、语序和时态.
1 if或whether不能和that 或其它连词（副词）同时使用,也不能省去.
2 if或whether引导的宾语从句时,虽具有疑问意义,但从句语序应用陈述句语序.
3 if或whether引导的宾语从句应和主句的时态保持一致.即主句为一般现在时,从句用任一种时态；主句为一般过去时,从句则用过去时中的任一种时态.
三、if和whether的区别：
1 在动词不定式之前只能用whether .
2 在whether …… or not 的固定搭配中.
3 在介词后,只能用whether.
4宾语从句放在句首表示强调时,只能用whether .
5用if会引起歧义时,只用whether.如用whether可避免歧义.一、Do you know if/ whether he can come here on time?
二、 Can you tell me who can runfastest in class?
三、 Can you tell me what is the advantage of western fast food?
四、Do you know if / whether it is polite to eat up the food on your plate?