问题 单项选择题

There is virtually no limit to how one can serve community interests, from spending a few hours a week with some charitable organization to practically full-time work for a social agency. Just as there are opportunities for voluntary service (1) (VSO) for young people before they take up full-time employment, (2) there are opportunities for overseas service for (3) technicians in developing countries. Some people, (4) those who retire early, (5) their technical and business skills in countries (6) there is a special need.

So in considering voluntary or (7) community service, there are more opportunities than there (8) were when one first began work. Most voluntary organizations have only a small full-time

(9) and depend very much on volunteers and part-timers. This means that working relationships are different from those in commercial organizations, and values may be different. (10) some ways they may seem more casual and less efficient, but one should not (11) them by commercial criteria. The people who work with them do so for different reasons and with different (12) , both personal and (13) . One should not join them (14) to arm them with professional experience; they must be joined with commitment to the (15) , not business efficiency. Because salaries are (16) or non-existent many voluntary bodies offer modest expense. But many retired people take part in community service for (17) , simply because they enjoy the work.

Many community activities possible (18) retirement were also possible during one’s working life but they are to be undertaken (19) seriously for that. Retired people who are just looking for something different or unusual to do should not consider (20) community service.

7()

A.paying

B.paid

C.to be paid

D.pay

答案

参考答案:B

解析:

考查过去分词的用法。所选词应该与or前的voluntary对应,因此,paid"付费的”为正确答案,作定语。

实验题

(1)实验室可用甲酸与浓硫酸共热制备一氧化碳:HCOOH浓硫酸========H2O+CO↑,实验的部分装置如下图所示。制备时先加热浓硫酸至80℃—90℃,再逐滴滴入甲酸。

Ⅰ制备CO     Ⅱ        Ⅲ收集CO

①从下图挑选所需的仪器,画出Ⅰ中所缺的气体发生装置(添加必要的塞子、玻璃管、胶皮管,固定装置不用画),并标明容器中的试剂。

                          

分液漏斗 长颈漏斗    蒸馏烧瓶    集气瓶   温度计

②装置Ⅱ的作用是                                        

(2)实验室可用甲酸制备甲酸铜。其方法是先用硫酸铜和碳酸氢钠作用制得碱式碳酸铜,然后再与甲酸斥制得四水甲酸铜[Cu(HCOO)2·4H2O]晶体。相关的化学方程式是:

2CuSO4+4 NaHCO3="=" Cu(OH)2·CuCO3↓+3CO2↑+2Na2SO4+H2O

Cu(OH)2·CuCO3+4HCOOH+ 5H2O="=2" Cu(HCOO)2·4H2O+ CO2

实验步骤如下:

Ⅰ、碱式碳酸铜的制备:

③步骤ⅰ是将一定量CuSO4·5H2O晶体和NaHCO3固体一起放到研钵中研磨,其目的是       

④步骤ⅱ是在搅拌下将固体混合物分多次缓慢加入热水中,反应温度控制在70℃—80℃,如果看到           (填写实验现象),说明温度过高。

Ⅱ、甲酸铜的制备:

将Cu(OH)2·CuCO3固体放入烧杯中,加入一定量热的蒸馏水,再逐滴加入甲酸至碱式碳酸铜恰好全部溶解,趁热过滤除去少量不溶性杂质。在通风橱中蒸发滤液至原体积的1/3时,冷却析出晶体,过滤,再用少量无水乙醇洗涤晶体2—3次,晾干,得到产品。

⑤“趁热过滤”中,必须“趁热”的原因是                                

⑥用乙醇洗涤晶体的目的是                                              

问答题