你所在线因为某个员工近期状态不佳总是出现人为失误导致，本线碎片，品质和产量一直不理想

人体缺乏维生素C（简写“VC”）就会患坏血病，哥伦布探险时的许多船员就因此而死亡．如图所示为某种“维生素C”说明书的一部分．请你回答：

（1）“VC”中含有　　　　种元素．

（2）若正常成人每天对“VC”的最低需要量为60mg．

①当“VC”完全来自上图的“维生素C”，则每天至少服用　　　　次；

②当“VC”完全来自某种新鲜蔬菜（每1000g这种蔬菜含“VC”120mg），则每天至少应食用这种蔬菜_______g．

（3）取2片“维生素C”溶于水，滴入紫色石蕊试液变红色，说明“VC”的溶液显_________性；加热该溶液至沸腾，红色消失，表明“VC”受热时易被破坏，那么在烹调新鲜蔬菜时要减少“VC”的损失，应采取的措施之一是　　　　　　　　　　　　　　．

养鱼缸长久不换水，缸的内壁上会长有绿膜，水会变成绿色，这是由于（　　）

A．葫芦藓的生长

B．蕨的生长

C．原叶体的生长

D．绿色藻类的生长

严重二尖瓣狭窄时，不易发生下列哪种并发症

A．肺水肿

B．亚急性细菌性心内膜炎

C．右心衰竭

D．肺部感染

E．房颤

班集体具有促进学生社会化发展和促进学生（）发展的双重功能。

阅读理解

     A lot of people are their own enemies. They regard themselves as unlikely to succeed in college and

often feel that there have been no accomplishments (成就) in their lives. In my first year of college

especially, I saw people get themselves down too quickly. There were two students in my class who failed the first test and seemed to give up immediately. From that day on, they walked into the classroom carrying defeat on their shoulders the way other students carried textbooks under their arms. When they

disappeared for good(长久地), no one took much notice, for they had already disappeared in spirit after

that first test.

     I have really wanted to shake them by the shoulders and say: "You are not dead. Be proud and pleased that you have brought yourself here to college. Breathe. Hope. Act." Such people should not use

self-doubts as an excuse for not trying. They should pull themselves together and get to work. They should start taking notes in class and trying to learn. Above all, they should not give up without even trying.

1. The phrase "get themselves down" (Para. 1) probably means ______.

A. tell lies  

B. lose confidence    

C. avoid dangers    

D. waste time

2. When the two students dropped out (退学), no one took much notice because ______.

A. they had long lost heart in class performance

B. they were absent from class too often

C. they didn't get on well with other students

D. they were so much cut off from the rest of the class

3. According to the passage, the two students failed in their study because of their ______.

A. shyness    

B. proudness    

C. self-doubt    

D. laziness

4. The author thinks that the two students should ______.

A. give up their college education        

B. learn from other students

C. feel happy because they are in college      

D. try hard before giving up