用己酸制备α-溴代己酸,反应式为______。

题型:填空题

问题:

用己酸制备α-溴代己酸,反应式为______。

考点:普通考研农学联考农学硕士联考化学
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如果收入200元记作+200元,那么支出150元,记作(    )元.

题型:填空题
某中学共有学生2000人,各年级男,女生人数如下表:
一年级二年级三年级
女生373xy
男生377370z
已知在全校学生中随机抽取1名,抽到高二年级女生的概率是0.19.
(1)现用分层抽样的方法在全校抽取48名学生,问应在高三年级抽取多少名?
(2)已知y≥245,z≥245,求高三年级中女生比男生多的概率.
题型:填空题

短文该错 (共10小题; 每小题1分, 满分10分)

One day, while my friend and I was traveling through Germany, we were not very hungry but we only had a little money. We decided stop at a village market to buy something to eat. We choose the cheapest biscuits and ate it under a tree. We thought the biscuits were great. “Let’s got some more,” I said, “They’re cheap and they really taste well.” My friend could read some German, and I couldn’t, so I gave her the biscuit bag to find the name. She looked at it and started to laugh, “How are you laughing?” I asked. “Because of they’re dog biscuits!” She said.

题型:填空题

对在坡道上摘挂车辆下列叙述正确的是()

A、摘车时,先防溜后摘车

B、摘车时,先摘车后防溜

C、挂车时,先挂妥后撤防溜

D、挂车时,先撤防溜再挂车

题型:填空题

聚合物水泥防水涂料用于地下防水工程时,必须测试的项目为()。

A、低温柔性

B、不透水性

C、抗渗性

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