machine/ machines
【问】 
(TOEFL教程)
请说明上面句子的错误何在。
【答】 按照英语惯用法，名词充当定语时，一般采用单数形式。因此，应将machines改为ma-chine。更详细的情形，请参阅singular or plural条。
请做下面的英语试题：
Idaho 
first 
the states 
production. (TOEFL， 84. 5)
赵振才 编著.英语常见问题解答大词典.哈尔滨：黑龙江人民出版社.1998.第676页.
- continue to do/doing
- continuous/continual
- contrary
- contrast
- control
- convenient to/for
- conversely
- convince/be convinced
- convince sb. of/convince sb. to do
- cool
- copular verbs(联系动词)
- corner
- corner
- corporation
- corps/corpse
- correspond to/ correspond with
- cost
- costly/precious
- cost/price
- could
- could have done
- could/might
- couldn't have done
- coul dn't have done
- couldn’t have done/cannot have done