????:1????????:????????????

2???????

3??????????

4?????sn

5???????

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

????1?????6?? (????????? ???????????????????)??????????????????????6?,??????????,????????????????????????????

?????,??????????????????2050??,????????2019?????????,???????,?????40%?

??????????????????????????,?490??????????????,?????????7000??(1???2.4????)??????

?,??30%??????,?????????,??????????????????????

?,??????,?????(??????????????) ????:???