问题 单项选择题

进程所请求的一次打印输出结束后,将使进程状态从

A) 运行态变为就绪态
B) 运行态变为等待态
C) 就绪态变为运行态
D) 等待态变为就绪态

答案

参考答案:D

解析: 运行中的进程有3种状态:运行状态、就绪状态和等待状态。
运行状态:是指进程已获得CPU,并且在CPU中执行的状态。就绪状态:是指进程已具备运行条件,但由于没有获得CPU而不能运行所处的状态,一旦CPU分配给它,就可以运行。等待状态:是指进程因等待某种事件发生而暂时不能运行的状态。例如,当两个进程竞争使用同一资源时,没有占用该资源的进程便处于等待状态。它必须等到该资源被释放后才可以去使用它。引起等待的原因一旦消失,进程就变为就绪状态,以便在适当的时候投入运行。

多项选择题
完形填空

What do you do when you are in trouble on a lonely island? Surely you need to   a way to get in touch with the outside world. Your best   of doing this is to draw the attention of a passing plane.

The smoke from a fire can be seen from far away,   it is a good way to attract attention. If the weather is dry, it's   to start a fire. But remember that fires can be very dangerous if they are out of control.    make a fire unless you're sure that it can't spread. If the ground is dark,   smoke can be seen more easily. Green grass and leaves produce white smoke.

It's a good idea to make some   , too. For example, "F" means "I need food and water'', "IF'   "I need medicine" and “I” for "I am too    hurt to move from here". These are useful symbols. Use large pieces of wood to make them. If you   find any wood, use earth.

You can be found more easily in this way.                               

小题1:A. give            B. find            C. show

小题2:A. place           B. service          C. chance

小题3:A. so             B. but             C. or

小题4:A. hard         B. easy           C. impossible

小题5:A. Never       B. Always        C. Sometimes  

小题6:A. light          B. black            C. blue

小题7:A. plans          B. rules            C. symbols

小题8:A. looks for      B. waits for         C. stands for

小题9:A. quietly         B. badly            C. slowly

小题10:A. can’t         B. mustn’t          C.needn’t