猜谜语。
身穿大皮袄,野草吃个饱,过了严冬天,献身毛。( )
绵羊
Mr. Mao, who as a construction worker for over 8 years, is now a distinguished lawyer in this country.
A.has worked
B.had worked
C.worked
D.has been working
简述事务的性质。