水管锅炉的水冷壁是指设在炉膛壁面的（）。

A．用水冷却的钢板

B．有水强制循环的管排

C．构成自然循环下降管的密集管排

D．构成自然循环上升管的密集管排

— Congratulations, Mary!

— Thanks. I have worked hard for years so as to pass the test, and now I’ve ______ at last

A．finished it

B．made it

C．got it

D．worked it