BOD表示()A.用强氧化剂氧化水中有机物所消耗的氧量  B.容易氧化的有机物含量

题型:单项选择题

问题:

BOD表示()

A.用强氧化剂氧化水中有机物所消耗的氧量 

B.容易氧化的有机物含量 

C.一切有机物含量 

D.含碳和含氮有机物的含量 

E.需氧微生物分解有机物消耗水中溶解氧的量 

考点:环境卫生(医学高级)环境卫生综合练习环境卫生综合练习题库
题型:单项选择题

Mrs. Brown was much disappointed to see the washing machine she had had ____ went wrong again.

A.it

B.it repaired

C.repaired

D.to be repaired

题型:单项选择题

根据短文内容和首字母的提示,把所缺单词填写在短文后面的横线上。

     Many students often 1. c______  about school. They might feel they have too 2. m_______ work to

do sometimes, or think the rules are too 3. s_______. We must learn how to change these "problems" into

"challenges". Education is an important part of our 4. d_______. As young adults, it is our 5. d_______ to

try our best to deal with each challenge in our education with the 6. h_______ of our teachers.

1._______ 2._______ 3._______ 4._______ 5.________ 6._______

题型:单项选择题

电解质是指在水溶液中或熔融状态下能够导电的化合物。几位同学对此定义中关键词发表了以下理解或看法,你认为不正确的是 [ ]

A.“或”字意味着水溶液中、熔融状态下这两个条件只需具备其中之一就行了

B.“能够导电”是指该物质本身能够导电,而不是它发生反应后的生成物能导电

C.“化合物”指明了该物质不能是单质,更不能是混合物

D.像硫酸钡、碳酸钙这样难溶的化合物就不可能是电解质了

题型:单项选择题
已知x2+
2
y=
3
y2+
2
x=
3
,且x≠y,则
x2+y2
x+y
=______.
题型:单项选择题

补写出下列名篇名句的空缺部分。(每空缺1分,共8分)

小题1:鹏之徙于南冥也,                                ,去以六月息者也。(《逍遥游》)  

小题2:               ,内无应门五尺之僮;            ,形影相吊。(《陈情表》)

小题3:亦欲以究天人之际,            ,成一家之言。(《史记·报任安书》)  

小题4:恨相见得迟,            ,柳丝长玉骢难系,                    。(《长亭送别》)

小题5:真的猛士,                   ,敢于正视淋漓的鲜血。(《记念刘和珍君》)

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