They( )for shanghai on Friday.shall we go to see them off at

They( )for shanghai on Friday.shall we go to see them off at the train station
A left B were leaving
C have left D are leaving
c为什么不可以
Old people must ( )
A be spoken to politely B speak to polite C be spoken politely D speak polite
那个to为什么要有啊?c为什么不可以
It was （ ）weather that they decide to go out for a picnic.
A such fine B such a fine
为什么没有a
-I don not have a parner to play table tennis with.
-why ( )a sport club to practise a lot?
A don't join B not joining C not to join D don't you join
not 和why don't you 的区别
（ ）are you gong to write this story
-about five pages
A how often B how soon C how long D how fast
how long 表时间为什么可以说明故事的长短,可以表具体吗?

They( )for shanghai on Friday.shall we go to see them off at the train station
A left B were leaving
C have left D are leaving
答案d,c为什么不可以
D 是对的,语法知识：一般现在时表示将来计划中的事情
而C是 一般完成时,和提议不符,从题意看应该是将要在周五离开.
Old people must ( )
A be spoken to politely B speak to polite C be spoken politely D speak polite
答案a,那个to为什么要有啊?c为什么不可以
改为主动语态你就明白了
you must speak to old people politely
你对老人讲话要礼貌
其被动语态就为
old people must be spoken to politely.
和老人讲话要礼貌（中文还是采用了主动语态的翻译,否则就不伦不类了,老人必须被礼貌地讲话）
所以选 a （如果C改为speak politely 也可以,但是意思比较勉强 老人必须说话礼貌）
It was （ ）weather that they decide to go out for a picnic.
A such fine B such a fine
答案A,为什么没有a
很明显天气是不可数的,因此不能用 a 来修饰
-I don not have a parner to play table tennis with.
-why ( )a sport club to practise a lot?
A don't join B not joining C not to join D don't you join
答案d,请教why not 和why don't you 的区别
选 Why not 这句话就没有主语了 不能成为一个完整的句子
如此时就可以把疑问句改为陈述句
you join a sprot club to practise a lot.
一般疑问句
do you join a sprot club to practise a lot.
表原因的特殊疑问句
why do you join a sport club to practise a lot?
表原因的特殊疑问句的反问句
why don't you join a sport club to practise a lot?
（ ）are you gong to write this story
-about five pages
A how often B how soon C how long D how fast
答案c,how long 表时间为什么可以说明故事的长短,可以表具体吗?
how long 表示 "多长" 即可以表示时间的长短,也可以表示其他方面的长短