在泵的流量和转速不变,吸入口直径D0大致相等情况下,比转数ns低,则扬程()。
A.等于零
B.越小
C.不变
D.高
参考答案:D
听短文,填入所缺单词。
People in 1 like Christmas very much. They 2 it with their 3 . It usually comes in 4 . On
that day, children are very happy, 5 they can get lots of presents from their 6 . Usually, there is a
Christmas tree in their house. People sing and 7 . They all look very happy. At 8 , they have a nice
9 with a lot of delicious (美味的) 10 .
上司即将于2003年6月去美国一家公司参观考察,在此之前,他从未走出过国门。
请问:1.秘书应该在近期为他办理那些出国手续?如何办理?
2.秘书要提醒上司注意哪些问题? 3.上司对黄皮书了解不多,请帮助他解释一下。