though还可与别的词结合使用.如even though, as though等,although则无这种搭配功能.如: I’ll go and help them even though I stop my work. 即使我停下自己的活不干.我也要去帮助他们. 查看更多

 

题目列表(包括答案和解析)

阿司匹林(乙酰水杨酸)已应用百年,成为医药史上三大经典药物之一,至今它仍是世界上应用最广泛的解热、镇痛和抗炎药,也是作为比较和评价其他药物的标准制剂。乙酰水杨酸受热易分解,分解温度为128~135℃。某学习小组在实验室以水杨酸(邻羟基苯甲酸)与醋酸酐[(CH3CO)2O]为主要原料合成该物质,设计的合成路线为:
一、制备K
s*5u
二、提纯
方案1
方案2
主要试剂和产品的物理常数
名    称
相对分子质量
熔点或沸点(0C)



水杨酸
138
158(熔点)
微溶
易溶
易溶
醋酸酐
102
139.4(沸点)
反应
可溶
易溶
乙酰水杨酸
180
135(熔点)
微溶
可溶
微溶
请根据以上信息回答下列问题:                   
(1)①合成阿斯匹林时,还会生成一些副产品,其中有一种是高分子,为了分离此物质,方案1中加入A物质为      溶液。
②本方案抽滤后进行洗涤,其具体操作是       
(2)方案2为改进的提纯方法,称为重结晶提纯法。
①该方案中步骤1除了选用乙酸乙酯外,还可选择下列哪些
试剂      
A. 乙醇      B. 蒸馏水      C. 乙醚   
②步骤2回流的装置如图所示,写出仪器a的名称      ,使用温度计的目的是      ,冷凝水的流向为       

③方案2所得产品的有机杂质要比方案1少的原因是      
(3)该学习小组在实验中原料用量:2.0g水杨酸、5.0ml醋酸酐(ρ=1.08g·cm-3),
最终称量产品m="2.2g" ,则乙酰水杨酸的产率为       。

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(6分)生物防治是利用________防治病虫害的技术,这种技术不仅可节省经费,还可减轻使用农药而造成的环境污染,主要包括以鸟治虫、________和________三个方面。

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(6分)生物防治是利用________防治病虫害的技术,这种技术不仅可节省经费,还可减轻使用农药而造成的环境污染,主要包括以鸟治虫、________和________三个方面。

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完形填空(二)(本题共15小题,满分30分)

阅读下面短文,根据文意,将方框内所给的词或短语的适当形式填入相应的空白处,使短文的意思完整。(每个词只能使用一次)(本题共十小题,每小题2分,满分20分)

last, save, neighbourhood , energy, again, so that ,possible,

whether, everyday,  do harm to

We all need a healthy environment, but we produce waste every day and it___1__ our environment. Though we are young, we can still do something to help. In fact, even the simplest __2__activities can make a real difference to the environment. Here are some ideas for you.

Reduce means “use less”. Don’t waste things. This ___3__money and reduces pollution and waste going into the environment. Before we buy something new, think __4___it is really necessary—or maybe the old one will be just as good! When we do buy things, choose local products if __5____ and try not to buy too many things from abroad.

Reuse means “use again”. Use things for as long as possible. When we buy things, make sure that they __6__ a long time. We should look after them__7__ they will last and we should repair them if we can instead of  throwing them away and buying new ones. Don’t use a paper cup or a paper bag. It’s better to use a china cup and a lunch box because you can use them __8_.

Recycle means “change things into something else”. Although it takes __9__ to change something into something else, it’s better than throwing things away or burning them. Find out what can be recycled in your_10___ and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees.

 

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完形填空(二)(本题共15小题,满分30分)
阅读下面短文,根据文意,将方框内所给的词或短语的适当形式填入相应的空白处,使短文的意思完整。(每个词只能使用一次)(本题共十小题,每小题2分,满分20分)

We all need a healthy environment, but we produce waste every day and it__【小题1】__ our environment. Though we are young, we can still do something to help. In fact, even the simplest _【小题2】__activities can make a real difference to the environment. Here are some ideas for you.
Reduce means “use less”. Don’t waste things. This __【小题3】__money and reduces pollution and waste going into the environment. Before we buy something new, think ___【小题4】____it is really necessary—or maybe the old one will be just as good! When we do buy things, choose local products if __【小题5】_____ and try not to buy too many things from abroad.
Reuse means “use again”. Use things for as long as possible. When we buy things, make sure that they __【小题6】__ a long time. We should look after them__【小题7】_ they will last and we should repair them if we can instead of  throwing them away and buying new ones. Don’t use a paper cup or a paper bag. It’s better to use a china cup and a lunch box because you can use them __【小题8】__.
Recycle means “change things into something else”. Although it takes ___【小题9】_ to change something into something else, it’s better than throwing things away or burning them. Find out what can be recycled in your_【小题10】__ and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees.

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