问题 单项选择题

薄膜蒸发浓缩效率高的主要原因是

A.蒸发温度高
B.药液沸点降低
C.药液蒸发时流速快
D.药液气化表面大
E.加热蒸汽温度高

答案

参考答案:D

解析:薄膜浓缩系指药液在快速流经加热面时,形成薄膜并且因剧烈沸腾产生大量的泡沫,达到增加蒸发面积,显著提高蒸发效率的浓缩方法。选D。

选择题
单项选择题

When I first entered university, my aunt, who is an English professor, gave me a new English dictionary. I was (16) to see that it was an English-English dictionary, also known as a monolin-gual dictionary. (17) it was a dictionary intended for non—native learners, none of my classmates had one (18) , to be honest, I found it extremely (19) to use at first. I would look up words in the dictionary and (20) not fully understand the meaning, I was used to the (21) bilingual dic-tionaries, in which the words are (22) both in English and Chinese, I really wondered why my aunt (23) to make things so difficult for me. Now, after studying English at university for three years, I (24) that monolingual dictionaries are (25) in learning a foreign language.

As I found out, there is (26) often NO perfect equivalence(对应) between two (27) in two language. My aunt even goes so far as to (28) that a Chinese "equivalent" can never give you the (29) meaning of a word in English! (30) , she insisted that I read the definition(定义) of a word in a monolingual dictionary (31) I wanted to get a better understanding of its meaning. (32) , I have come to see what she meant.

Using a monolingual dictionary for learners has helped me in another important way. This dictionary uses a(n) (33) number of words, around 2,000, in its definitions. When I read these definitions, I am (34) exposed to (接触)the basic words and learn how they are used to explain objects and ideas. (35) this, I can express myself more easily in English.

22()

A. explained

B. expressed

C. described

D. created