每根换出的长钢轨的长度一般不得大于（）。
A.50m
B.100m
C.500m
D.800m
参考答案：C
The film Kung Fu Panda ______ is ______ the evening. [ ]
A. on in
B. in on
C. on at
D. at in
辐射会导致人体细胞的哪些损伤？
