[Bug]: 生成的课堂对于拼音和英文分不清

### Bug Description

拼音课堂中间穿插英文，https://open.maic.chat/classroom/xTFzbn3Lse

### Steps to Reproduce

生成一个拼音课堂

### Expected Behavior

里面教的是拼音，而不是英文

### Actual Behavior

拼音和英文混合输出

### Deployment Method

Other

### Browser

_No response_

### Operating System

_No response_

### Relevant Logs / Screenshots

```shell

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### Additional Context

_No response_