刚入门，有点难搞，等dlao

3.将字典studentGradeDict={'张三':85,'韩雪':70,'李四':93,'刘梅':61'}中的项成绩由高到低，打印显示学生的名字。

studentGradeDict = {'张三': 85, '韩雪': 70, '李四': 93, '刘梅': 61}
studentGradeDict1 = sorted(studentGradeDict.items(), key=lambda x: x[1], reverse=True)
for i in studentGradeDict1:
    print(i[0],end=" ")

studentGradeDict=dict(sorted(list(studentGradeDict.items()),key=lambda x:-x[1]))
print(studentGradeDict.keys())