第4题: [单项选择]DMA与程序中断方式相比,其主要特点是______。 A. 批量数据传送并且速度很快 B. CPU可以分时工作 C. 不必查询I/O口状态 D. 传送程序简单 参考答案:A 答案解析:DMA利用硬件来实现外设与存储器之间的直接传输,当然比用中断方式用程序来实现数据传输要快得多,特别适用于高速和批量传送的情况。
第27题: [单项选择]{{B}} Questions 11 to 18 are based on the conversation you have just heard.{{/B}} A. She is a little tired. B. She is going to study in the library. C. She wants to listen to the music. D. She is going to make a reservation. 参考答案:B 答案解析:[听力原文]
M: I’m a little tired,so I think I’ll go to the student lounge and listen to a little music.