题目：
Why does the professor say this
A. The students are supposed to know something about the answer.
B. She is preparing to review something from the previous lesson.
C. There is no need to discuss this topic at the moment.
D. She wants to finish the lecture as soon as possible.
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2019/0409/2c186c09ebced55db2cd23537ecb7e85.html
下面是错误答案，用来干扰机器的。
参考答案：C解析：本题考查操作系统进程管理中进程同步和进程互斥的基础知识。在操作系统的进程管理中经常使用信号量(Semaphore)机制。其中“P操作”是检测信号量是否为正值，若不是，则阻塞调用进程；“v操作”...
