二、三、四、五级石油库的油罐区和装卸区消防道路的路面宽度不应小于()m。
A、3.5
B、4.0
C、6.0
D、7.0
参考答案:B
It was from the Lowell Laboratory that the ninth________, Pluto, was sighted in 1930.
A.planet
B.constellation
C.stardom
D.satellite
据国家标准规定,热水管的代号用()。
A、R
B、S
C、N
D、H