1. [第五题.png](https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202104/6efbda08aed046e5ab56a6c7653d5f78.png)![5c.png](https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202104/85df906f593b4210be936eddee5d6e92.png)