?? ????????
????:1????????50?????:????????
2????????
3???????????12????
4?????
5?????????
?
??,???,?????????,1970????????4????,??,????
?
????,????????,?,1972??12????,?????????,??
???
??,??,??,1977?????5????,??,??
????
?,??,??,1980?8????,????,???
??:????