每日科技英文45: nodejs的内核-libuv库简介

今日要点:

1. libuv介绍
2. 情态动词之must表示推测

Libuv Overview

libuv is a multi-platform support library with a focus on asynchronous I/O. It was primarily developed for use by Node.js, but it's also used by Luvit,Julia, pyuv, andothers.

• with a focus on asynchronous I/O：做定语修饰library, 关注与异步文件流

• be primarily developed for use by: 主要被开发出来用于...

Feature highlights

1. Full-featured event loop backed by epoll, kqueue, IOCP, event ports.

• be backed by： 被...所支持
  linux使用epoll,unix中使用kqueue,windows中使用IOCP（IO完成端口），Solaris event ports（？？？)

2. Asynchronous TCP and UDP sockets

3. Asynchronous DNS resolution

4. Asynchronous file and file system operations

5. File system events

6. ANSI escape code controlled TTY

7. IPC with socket sharing, using Unix domain sockets or named pipes (Windows)

8. Child processes

9. Thread pool

10. Signal handling

11. High resolution clock

12. Threading and synchronization primitives

今日语法小知识: 情态动词之must表示推测

1. must用在肯定句中表示较有把握的推测，意为"一定"。

2. must表对现在的状态或现在正发生的事情的推测时， must 后面通常接系动词be 的原形或行为动词的进行式。
   You have worked hard all day.You must be tired. 你辛苦干一整天，一定累了。（对现在情况的推测判断）
   He must be working in his office. 他一定在办公室工作呢。
   比较：
   He must be staying there.
   他现在肯定呆在那里。
   He must stay there.
   他必须呆在那。

3. must 表示对已发生的事情的推测时，must 要接完成式。
   I didn't hear the phone. I must have been asleep. 我刚才没有听到电话，我想必是睡着了。

4. must表示对过去某时正发生的事情的推测，must 后面要接不定式的完成进行式。
   Why didn't you answer my phone call?
   Well, I must have been sleeping, so I didn't hear it.

5. 否定推测用can't。
   If Tom didn't leave here until five o'clock, he can't be home yet. 如果汤姆五点才离开这儿，他此时一定还未到家。