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

2?????

3?????vx

4?????

5????????95?

??????????12????20????? ??,????????????20???????????????????

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

??????????,??????????????????????,9???????5?????16????????????,?????,???????????????????,?????????????????????,20????????????????

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

??????,???,?????,???“??????????”?

?,21??????,????????????????(??????????????) ???????????????????????????????????????:???