空心阴极灯的阴极是用待测元素制做，灯内充有（）。
参考答案：低压惰性气体
Autumn coming, down ________.
A．do the leaves fall
B．the leaves will fall
C．fall the leaves
D．the leaves are falling
—I hear that a new park _______in the center of the city by 2012.
—That’s great
A. will build B. will be built C. was built
