1. ![第一题.png](https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202103/04a446b0edb34ec29286f9d2b5bee932.png)![C.png](https://image.zhihuishu.com/zhs/teacherExam_h5/COMMONUEDITOR/202103/b7140d2e1d9242a88dc74d3aa384dc70.png)