搜题请搜索小程序“爱下问搜题”
问题 单项选择题

一定时间和温度下，水体中有机污染物受微生物分解所耗去水体溶解氧的总量是：（）（883-30）

A、溶解氧

B、生化需氧量

C、化学耗氧量

D、悬浮物

E、混浊度

答案

参考答案：B

判断题

使用米桥式测量系统时，测量头选择错误，测量出的宽度数据错误。
查看答案
填空题

Beijing: The United States and North Korea had their first ________in four months here this afternoon as part of the ________negotiations on how to end North Korea’’s nuclear program, but diplomats played down prospects for________.James A. Kelly, assistant________, and Kim Yong II, North Korea’’s deputy foreign minister, met ________of formal discussions, ________on direct dialogue that began after a stormy meeting ________in which North Korea warned that it was moving quickly to ________nuclear arms.The Bush administration had insisted ________that it would only hold talks with North Korea ________because, it argued, only ________pressure would persuade North Korea to________. It got its way when North Korea dropped its insistence on ________and agreed, after extensive efforts by China, to hold unusual simultaneous negotiations with ________,________,________and ________as well as the United States.Though Bush administration officials had not ________talking privately with the North Koreans during________, the fact that Mr. Kelly and Mr. Kim met on the first day was seen as a sign of ________by the American side.
查看答案