题目

X、Y、Z为三种金属，已知①X＋H2SO4===XSO4＋H2↑ ②Y＋2ZNO3===Y(NO3 )2＋2Z ③Y与稀硫酸不反应，则下列符合要求的X、Y、Z分别是(  ) A．Fe Cu Ag  B．Cu Hg Ag  C．Mg Zn Fe  D．Fe Ag Cu 答案：AJoe, don't ________ now, you're improving all the time. It won't be long ________ you can speak good English. [　　] A．give in; untilB．give up; before C．give in; whenD．give up; after