题干

某种蔬菜离体叶片在黑暗中不同温度条件下呼吸速率和乙烯产生量的变化如下图所示,t1、t2表示10℃—30℃之间的两个不同温度。下列分析正确的是(    )

A:与t1相比,t2时呼吸速率高峰出现时间推迟且峰值低,不利于叶片贮藏

B:与t2相比,t1时乙烯产生量高峰出现时间提前且峰值高,有利于叶片贮藏

C:t1、t2条件下呼吸速率的变化趋势相似,t1>t2,t1时不利于叶片贮藏

D:t1、t2条件下乙烯产生量的变化趋势相似,t1<t2,t1时不利于叶片贮藏

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答案(点此获取答案解析)

C

同类题2

阅读下面短文,掌握其大意,然后从各题所给的A、B、C和D项中,选出最佳选项。

    When I first entered university, my aunt, who is an English professor, gave me a new English dictionary. I was 1to see that it was an English dictionary, also known as a monolingual dictionary.2it was a dictionary intended for non—native learners, none of my classmates had one, 3, to be honest, I found it extremely 4 to use at first. I would look up words in the dictionary and 5 not fully understand the meaning. I was used to the 6 bilingual dictionaries, in which the words are 7 both in English and Chinese. I really wondered why my aunt 8 to make things so difficult for me. Now, after studying English at university for three years, I 9 that monolingual dictionaries are 10 in learning a foreign language As I found out, there is 11 often no perfect equivalence(对应)between two 12 in two language. My aunt even goes so far as to 13 that a Chinese "equivalent" can never give you the 14 meaning of a word in English! 15, she insisted that I read the definition(定 义) of a world in a monolingual dictionary 16 I wanted to get a better understanding of its meaning. 17, 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) 18 number of words, around 2, 000, in its definitions. When I read these definitions, I am 19 exposed to(接触)the basic words and learn how they are used to explain objects and ideas. 20 this, I can express myself more easily in English.