问题 单项选择题

下列关于栈的叙述正确的是______。

A.栈按“先进先出”组织数据

B.栈按“先进后进”组织数据

C.只能在栈底插入数据

D.不能删除数据

答案

参考答案:B

解析: 栈是限定在一端进行插入与删除的线性表,允许插入元素的一端为栈顶,允许删除元素的一端为栈底,故选项C、D是错误的。栈项元素总是最后被插入的元素,也是最先被删除的元素:栈底元素则总是最先被插入而最后被删除的元素,即栈是按“先进后出”的原则组织数据的。

选择题
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When it comes to your skin, there is an extremely important fact that you must keep in mind: Your skin is the largest organ of your body. As an obvious result, skin health and maintenance(保养) is vital. Your skin does everything from protecting you from the elements to assisting you with breathing. Your skin keeps your body hydrated(含水的) and regulates your body's temperature. In the end, this really is only the beginning of all of the various vital functions that your skin provides to you.

Despite the extreme importance of a person's skin, the reality is that many people simply do not pay much attention to issues relating to the health of their skin. With that in mind, there are some prime tips and pointers that you must always keep in mind when it comes to the health and protection of your skin.

Protection against harmful rays from the sun is one of the most important steps that you need to take. With this in mind it is vitally important that you make certain you use solid protection when you go out into the sun.

Your diet also has a direct effect on the health of your skin. The most important aspect of your diet in relation to the health of your skin is to make certain that you eat a proper amount of food items that contain the proteins and nutrients necessary for cellular maintenance, repair and regeneration(再生). With this in mind, your skin cells actually rely on a sufficient amount of carbohydrates.

Water is also important to the Health of your skin. While you certainly have heard it before, it actually is true that you should drink at least eight 8-ounce glasses of fresh and pure water every day. There are many health benefits you can get from drinking water daily, including maintaining healthy skin.

Finally, when it comes to the health of your skin today and into the future you should avoid smoking all together. In addition, you should drink alcohol only in moderation. Both smoking and too much alcohol consumption can negatively affect the health of your skin in significant ways.

55.The underlined word elements in the first paragraph probably refers to _______.

A. bad weather                                          B. a favorable environment

C. all the chemicals                                          D. the cells making up the skin

56.The writer lists some of the functions of skin in the beginning part to _______.

A. make an analysis of the main topic of the passage

B. draw readers’ attention to the main topic of the passage  

C. give a brief introduction to the main topic of the passage

D. give the readers a summary of the main topic of the passage

57.Which of the following does not help maintain the health of skin?

A. Drinking alcohol in moderation.

B. Including adequate carbohydrates in diet.

C. Using solid protection when exposed to the sun.

D. Drinking enough fresh and pure water every day.

58.The most suitable title of the passage may be _______.

A. An essential organ of our body               B. Tips for soft and smooth skin

C. Habits and skin health                            D. How to keep our skin healthy