ϵͳķࣺ
򵥵Ľࣺ1豸2 
һ豸Ҫ
1ˮϵͳ
2ϵͳ
3ĭϵͳ
1ˮϵͳˮõҪˮ۸ˡЧáҪǣˮȴ͸ȼ ?
a˨ˮϵͳ(˨ϵͳ˨ϵͳ) 
bԶˮϵͳ
b1ʽԶˮϵͳصǲñʽͷʱ¶ʱʹͷĲѻ۽䣬ӶԶˮҪ¶Ȳ4 Ҳ70 Ľڡ
b2ԤˮϵͳϵͳĹܵѹѹ壬ƽʱܵˮģʱͨ̽ϵͳԤ÷ܵڹˮȻʽͷˮҪ¶ȵ4 Ҹ70Ľڡ
 b3ԶˮϵͳϵͳҪصǲÿʽͷʱͷͬʱˮҪΣռĽ   