离心泵入口管线的管径()泵出口管,但二者相差不能太大,否则产生气缚。 A.大于 B. 发布时间:2018-02-25 16:54 │ 来源:www.tikuol.com 题型:单项选择题 问题: 离心泵入口管线的管径()泵出口管,但二者相差不能太大,否则产生气缚。A.大于B.等于C.小于D.大于和等于
题型:单项选择题 The older she grows, the traditional food in her own country. [ ]A.the more she becomes interested B.the more interested she becomes C.the more interested she becomes in D.the interested she becomes more in 查看答案
题型:单项选择题 下列有关初生演替和次生演替的叙述中,正确的是()A.沙丘上进行的演替是初生演替,火山岩上进行的是次生演替B.初生演替形成的群落内无竞争现象,次生演替形成的群落内竞争明显C.初生演替所需时间较长,次生演替所需时间较短D.初生演替能形成森林,次生演替很难形成森林 查看答案