1、the policy having been made,the next problem was how to ca

1、the policy having been made,the next problem was how to carry it out.为什么要用ing分词啊?
2、no such thing as a ghost exists in the world.为什么不可以这么说no such a thing as ghost?
3、intellect is to the mind what sight is to the body.怎样分析这句子的结构啊
4、lack in与lack of 有什么区别啊
5、that being the case,we have to make some changes in our plan.为什么用being,不用be
6、since than后面的动词用什么时态啊
7、he found Irene seated at the piano with her hands on the keys.为什么用seated,不用seating