问题 问答题 简答题

什么是可重用性?如何通过提高软件的可重用性来提高软件的可维护性?

答案

参考答案:可重用性是指同一事物不加修改或稍加修改,就可以在不同环境多次重复使用。大量使用可重用软件构件,可大幅提高软件的可维护性。主要体现在两个方面:

1.可重用构件通常都是组装成功的部件,加上每次重用又都会进一步完善部件,因此可以大幅提高软件的可靠性,而改正性维护要求会降低。

2.很容易修改可重用的软件构件,使之适应新的应用环境,因此软件中使用可重用构件越多,软件的适应性维护和完善性维护也越容易。

阅读理解

If you see someone drowning, speed is very important. Once you get him out of the water, if he isn't breathing, you have four minutes before his brain is completely destroyed. Support his neck, move his head back and press his chin upwards. This stops the tongue blocking the airway in the throat and is sometimes enough to get him breathing again. If that doesn't work, start mouth-to-mouth breathing. Press his nostrils (the two holes at the end of your nose, through which you breathe and smell things) together with your fingers. Open your mouth and take a deep breath. Blow into his lungs until his chest rises, then remove your mouth and watch his chest fall. Repeat twelve times a minute. Keep doing until professional help arrives.

To bring a child back to life, keep your lips around his mouth and gently blow into his mouth. Give the first four breaths as quickly as possible to fill the blood with oxygen. If, in spite of your efforts, he starts turning a blue-grey colour, and you can feel no pulse(脉搏), then pressing is the last chance of saving his life.

With arms straight, rock forwards, pressing down on the lower half of the breastbone. Don't be too hard or you may break a rib. Check how effective you are by seeing if his colour improves or his pulse becomes independent to your chest pressing. If this happens, stop the pressing. Otherwise continue until rescue arrives.

小题1:If you want to save someone drowning, you __________.

A.have to pull off his clothes first .

B.should try to get him out of water as quickly as possible.

C.should first make out who he is.

D.ought to throw a life coat to him first .小题2:Once a person stops breathing, it means ___________.

A.you have no more than 4 minutes to bring him to life again .

B.his brain is completely damaged .

C.he has passed away.

D.there is no way to save his life .小题3:To press his chin upwards is a way to _____________.

A.keep the tongue from blocking the airway in the throat .

B.prevent the tongue from stopping the airway in the throat .

C.wipe the tongue out of the throat .

D.see if he can possibly be saved .小题4:If the drowning boy has no pulse,_____________.

A.press his chin upwards is enough to get him breathing .

B.blow air into his mouth is sure to save his life .

C.press his nostrils together with your fingers can work .

D.press is the last chance of saving his life .小题5:Which of the following statement is true?

A.Don’t stop pressing his chest, if the drowning man starts breathing again.

B.If you see someone drowning, you must give him mouth-to-mouth breathing.

C.If a man does not breathe for four minutes, his brain will be completely destroyed.

D.When pressing, you can do it as hard as you can.

单项选择题