???????????????????????????? ???????????? ????????????????

a.?????????????????????????????4???????????

1)????????????1000????;

2)????????????2000????;

3)????????????4000????;

4)????????????8000????;

b.????????????????????л?????????Щ??????????????????????????????????????Ч????

1)?????????????????t????

2)????????????ɡ?

3)?????????????????????????????????????檔

4)?????????????????????(???)???????е???????????????????????t??????????1000*??????????

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