Update README.md

coderhare · web-flow · commit 89a45400e089 · 2021-10-18T19:18:50.000+08:00
diff --git a/README.md b/README.md
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+| 第四章：Hack Machine language                       |  [note4](https://github.com/coderhare/nand2tetris/blob/main/Notes/%10%E7%AC%AC%E5%9B%9B%E7%AB%A0%EF%BC%9A%10Hack%20Machine%20language.md)         |
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 | 第六章：Hack Assembler | [note6]() |
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