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

2?????98??

3???????????

4???????

5???????

?????????????“??”????????????????? ???? ??? ????????????C919?ARJ21???????? ????????????? ?? ????????????????C919?????ARJ21????? ????? ?? ??“?”???K-8?????????????? ???????? ? ????????????????????“?????”???K-8??????? ??????????? ????? ????C919????????????????? ? ??? ???????? ?? ????? ????????????????? ? ? ??“??????”????? ? ??? ???ARJ21???????? ????? ???? ??????????????:???