周末开始倒腾jupyter notebook，记录一下，供后学参考：
下载速度
切换下载镜像后，你的速度会很快。
如何设置快捷键：
只能修改命令模式下的快捷键。
This dialog allows you to modify the keyboard shortcuts available in command mode. Any changes will be persisted between sessions and across environments. You can define two kinds of shorctuts: key combinations and key sequences.
你可以设置两种快捷方式：组合键和序列键。
Key Combinations:
第一种，组合键：
Use hyphens - to represent keys that should be pressed at the same time.用"-"来表示两个按键同时按下。
This is designed for use with modifier keys: Cmd, Ctrl, Alt ,Meta, Cmdtrl, and Shift.这是专门为修饰键设计的。（修饰键，又称辅助键，功能键，包括cmd，ctrl，alt，meta，cmdtrl以及shift。）
Cmdtrl acts like Cmd on OS X/MacOS and Ctrl on Windows/Linux.
At most, one non-modifier key can exist in a key combination.
通常，一个非修饰健可以存在于一个组合键中。
Multiple modifier keys can exist in a key combination.
多个修饰健也能够存在于一个组合键中。
Modifier keys need to precede the non-modifier key in a combination.修饰健需要和非修饰健一起联合使用。
Valid Examples: Shift-a, Ctrl-;, or Ctrl-Shift-a.
有效：“shift-a";或者"ctrl-shift-a".
Invalid Examples: a-b and a-Ctrl-Shift.
无效："a-b"，"a-ctrl-shift"。
Key Sequences:
第二种，序列键。
Use commas , to represent keys that should be pressed in sequence.用逗号来分隔需要出现在序列键种的按键。
The order in which keys must be pressed exactly matches the left-to-right order of the characters in the sequence, with no interruptions.按键必须不间断的，从左到右的，与序列键一致的顺序按下。
E.g., h,a,l,t would be triggered by typing h a l t but not h a a l t or a h l t.
例如，"h,a,l,t"，只会被"halt"触发，不会被"haalt"触发。
Sequences can include the same key multiple times (e.g., d,d).
序列键可以多次使用同一个键。（如"d,d"）
You cannot include any pairs of sequences where one is a 'prefix' the other.你不能给序列键加前缀。
E.g., d,d,d cannot be used a the same time as d,d.
如，"d,d,d"和"d,d"是不一样的。
Key combinations are unique elements that can be used in a sequence.组合键能够当作独立的元素在序列键中使用。
E.g., Ctrl-d,d and d,d can exist at the same time and are both valid key sequences.
如："ctrl-d,d"和"d,d"能够同时存在且有效。
Additional notes:
另外，请注意：
The case in which elements are written does not change the binding's meaning. E.g., Ctrl-D and cTrl-d are the same key binding. Thus, Shift needs to be explicitly included if it is part of the key binding. So, for example, if you set a command to be activated by Shift-D,D, the second d cannot be pressed at the same time as the Shift modifier key.
元素的大小写不影响其意思，如"Ctrl-D"和"cTrl-d"是一样的组合键。因此，如果"shift"包含在组合键中，必须要明确说明。例如，你设置一个快捷键"SHIFT-D,D"，第二个D不能和shift键同时按下。
Valid modifiers are specified by writing out their names explicitly: e.g., Shift, Cmd, Ctrl, Alt ,Meta, Cmdtrl. You cannot use the symbol equivalents (e.g., ⇧, ⌘, ⌃, ⌥); refer to developer docs for the corresponding keys (the mapping of which depends on the platform you are using).You can hover on the name/description of a command to see its exact internal name and differentiate from actions defined in various plugins.
修饰健必须完整的写出来才有效，例如"shift,cmd,ctrl,alt,meta,cmdctrl"等， 您不能使用等效符号（例如，⇧，⌘，^，⌥）; 请参阅开发人员文档以获取相应的按键信息（其映射取决于您使用的平台）。您可以将鼠标悬停在命令的名称/描述上，以查看其确切的内部名称，并区别于各种插件中定义的操作。
Changing the keybindings of edit mode is not currently available.
当前还不能修改编辑模式下的组合键。
