of 、for、 to 、with的区别与用法
例如（1）the government should further strengthen the supervision and control of the production and circulation of plastic bags.其中的control of the procduction为什么不能用to呢.（2）I am writing to ask if you can recommend a child as the recipient of my financial assistance.其中的的writing to ask 可以换做writing for asking （3）thank you very much for having given me this opportunity to take such a promisiong position in such a best-selling magazine.其中的thank you very much fo having give 可以换做to having give 还有with,这几个词我老是分不清楚,不知道什么时候该用哪一个,希望有人能帮帮我 还有那个可数名词,是不是前面不加冠词之类的都要用复数?