A:
B:
C:
D:
已知X、Y、Z三种金属能发生下列反应:X+H2SO4═XSO4+H2↑,Y+Z(NO3)2═Y(NO3)2+Z,Z+X(NO3)2═Z(NO3)2+X,则X、Y、Z三种金属与氢的活动性由强到弱的顺序为( )
如图,能用∠1,∠ACB,∠C三种方法表示同一个角的是( )
—Mr. Smith, Can you give us some advice on how to learn English well'?
—Remember, Nothing can be learned well ______hard work.