Merge pull request #9 from Kukicosmos/patch-1

Update readme.md

readme.md

@@ -13,7 +13,7 @@
 | ------ | -------------------------------------------------- | ------ | ----- | ------------ | ------------------- |
 | Part 0 | Introduction to language design and implementation | [lec0](./course/lecture0-intro/lec0.pdf)       |[课时一（上）](https://www.bilibili.com/video/BV1HNp3eUEcA/)、[课时一（下）](https://www.bilibili.com/video/BV1RipgeBEQd/)       |              |
 | Part 1 | MoonBit crash course                               | [lec1](./course/lecture1-crash-course/lec1.pdf) | [课时二](https://www.bilibili.com/video/BV1WtHQewEGj/) |              |                     |
-| Part 2 | Parsing                                            | [lec2](./course/lecture2-lex-parse/) |       |  [lec2.mbt](./course/lecture2-lex-parse/lec2.mbt) |                     |
+| Part 2 | Parsing                                            | [lec2](./course/lecture2-lex-parse/) | [课时三](https://www.bilibili.com/video/BV1Eq4EeyEES/?spm_id_from=333.999.0.0)      |  [lec2.mbt](./course/lecture2-lex-parse/lec2.mbt) |                     |
 | Part 3 | Semantics analysis and type inferences             |        |       |              |                     |
 | Part 4 | Bidrectional type checking                         |
 | Part 5 | IR designs (ANF, CPS, KNF)                              |