?????????????:??10???????

?????? ?????2??????????????6????????18?:

??,??????,2??????????????6???????????20??????8??20??,??????????????????????6~8?,??,??????10?????????????;??4~6?,???7~8?,?????10??????????8?,??????????????0??????????????????????,????6~8??

?????:

1?????;

2???;

3????????????????;

4???