????:1?????:????vx?

2?????????

3??????

4??????v

5???????????

????2?2??????????? ?????(BBC)????????,??2???1?,????????,????????????25%?,????????

???????????????,??,???1550?25%?????????????300??????????????????????????????????????2?????????????4??,1250????????????????21????

??????????,?????,???

??????????,??????????????,??????25%??????????,???????10%?

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