污水过格栅倾角宜采用()。
A.25°~35°
B.35°~45°
C.45°~75°
D.75°~90°
参考答案:C
The president of the university has been ___ for two years.
A.going
B.away
C.holiday
D.leaving
砂石反滤井围井高度以能使水不挟带泥砂从()顺利冒出为度,并应设排水管,以防溢流冲塌井壁。
A.底部
B.井口
C.井壁
D.井身