±500kV直流线路与公路交叉时,导线到1~3级公路路面最小距离不应小于( )。
A.10.0m; B.12.0m; C.14.0m; D.16.0m。
参考答案:D
Mr. Brown doesn’t feel at _______ease for the time being for _______ little money the present job brings him can hardly support his extended family.
A./; the
B.an; the
C.an; /
D.the; a
下列关于元素周期表的说法正确的是
A.元素周期表有七个横行,即七个周期
B.元素周期表有十八个竖行,即十八族
C.周期表中有七个主族,十一个副族
D.第ⅠA族又叫卤族