·2,447,543篇论文数据，部分数据来源于NoteExpress
每个用例都由一个椭圆形代表，用描述这个用例将要执行什么样的行为的说明型陈述进行标注。
Each use case is represented by an oval, and labeled with a declarative statement that describes what action the use case is intended to perform.
youdao
应用推荐
模块上移
模块下移
不移动