水平单向流洁净室风速测试点取距送风面（）m的垂直于地面的截面。
A.0.8
B.0.1
C.0.4
D.0.5
参考答案：D
— When are you going to Hainan?
— I am going there _____ June 8, 2007. [ ]
A. with
B. on
C. at
D. in
“由抽象上升到具体”的过程是理性认识回到实践的过程。 ( )
