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问题 选择题

长期以精米、精面为主食而副食很单调的人，唇和口角等容易发生炎症，这是因为食物中缺少（　　）

A．蛋白质

B．葡萄糖

C．无机盐

D．维生素B1

答案

人体对维生素的需要量很少，但维生素的作用却很大，如果缺乏某种维生素，就会表现出相应的缺乏症，如缺乏维生素B1会导致神经炎、脚气病、口角炎等症状．粗粮或粮食的麸皮中维生素B1的含量非常丰富，因此要多吃粗粮，如果长期以精米、精面为主食，就会缺乏维生素B1，而导致神经炎、脚气病、口角炎等．可见D符合题意．

故选：D

单项选择题

There are two types of people in the world. Although they have equal degree of health and wealth and other comforts of life, one becomes happy and the other becomes unhappy. This arises from the different ways in which they consider things, persons, events and the resulting effects upon their minds.
People who are to be happy fix their attention on the convenience of things: the pleasant parts of conversation, the well prepared dishes, the goodness of the wine and the fine weather. They enjoy all the cheerful things. Those who are to be unhappy think and speak only of the opposite things. Therefore, they are continually dissatisfied. By their remarks, they sour the pleasure of society, offend (hurt) many people, and make themselves disagreeable everywhere. If this turn of mind was founded in nature, such unhappy persons would be the more to be pitied. The intention of criticizing and being disliked is perhaps taken up by imitation. It grows into a habit, unknown to its possessors. The habit may be p, but it may be cured when those who have it realize its bad effects on their interests and tastes. I hope this little warning may be of service to them, and help them change this habit.
Although in fact it is chiefly an act of the imagination, it has serious results in life since it brings on deep sorrow and bad luck. Those people offend many others; nobody loves them, and no one treats them with more than the most common politeness and respect. This frequently puts them in bad temper and draws them into arguments. If they aim at getting some advantages in social position or fortune, nobody wishes them success. Nor will anyone start a step or speak a word to favor their hopes. If they bring on themselves public objections, no one will defend or excuse them, and many will join to criticize their wrongdoings. These should change this bad habit and be pleased with what is pleasing, without worrying needlessly about themselves and others. If they do not, it will be good for others to avoid any contact with them. Otherwise, it can be disagreeable and sometimes very inconvenient, especially when one becomes mixed up in their quarrels.

The phrase "sour the pleasure of society" most nearly means "______".

A. have a good taste with social life
B. make others unhappy
C. tend so scold others openly
D. enjoy the pleasure of life
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单项选择题

水平安定面固定的飞机，常用升降舵调整片来控制杆力，飞行中，如果把杆力配平在较大速度，在小速度飞行时，如果不动调整片，刚（）.

A.需施加一个较大的拉杆力才能使飞机保持仰平衡

B.需施加一个较大的推杆力才能使飞机保持俯仰平衡

C.可能施加拉杆力，也可能加推杆力
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