A:the 1980s; his twentie
B:the 1980s; the twentie
C:the 1980s; twentie
D:1980s; the twentie
有X、Y、Z三种金属,把Y投入X(NO3)2溶液中,Y表面有X析出;把X投入Z(NO3)2溶液中,X表面有Z析出。X、Y、Z三种金属的活动性由强到弱的顺序是( )
《守株待兔》这则寓言告诉我们( )