Every minute must be made full use of ____ our lessons, for the final examination is coming.

A．going over

B．to go over

C．go over

D．to going over

已知三种二价金属的活动性顺序为X>Y>Z，某同学设计进行了如下实验，请你从理论上分析肯定不成功的实验是[ ]

A．实验一：X+YSO₄→XSO₄+Y

B．实验二：Z+YSO₄→ZSO₄+Y

C．实验三：X+H₂SO₄(稀)→XSO₄+H₂↑

D．实验四：Z+H₂SO₄(稀)→不反应