优化翻译

[vector090]

目标章节：多处

当前上游最新 commit：此处填写本项目英文版 https://github.com/javascript-tutorial/en.javascript.info 的最新 commit，例如 https://github.com/javascript-tutorial/zh.javascript.info/commit/b03ca00a992a73aaf213970e71f74ac1c04def33

本 PR 所做更改如下：

调整部分翻译语句更加通顺自然。

文件名	参考上游 commit	更改（理由）

注意，参考上游 commit 是指你所修改的文件，在英文仓库中同名文件的对应 commit，即你此次提交的修改的依据。如果本 PR 你只是提交一个文字或者语句优化，并非根据上游英文仓库的修改而提交的更新，则请填无。

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1 out of 2 committers have signed the CLA.

:white_check_mark: vector090
:x: rootuc

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