学习UMl时候实际参考一个图解即可，发现图片都不是很清晰，google了一个高清图，分享给大家

不用刻意去记，用到的时候看看图即可。
在UML类图中，常见的有以下几种关系:泛化（Generalization）, 实现（Realization）,关联（Association）,聚合（Aggregation）,组合(Composition)，依赖(Dependency)

接口还有个棒棒糖表示法：

On April 25, according to CCTV news, yesterday was the seventh China Space Day. As of now, the Chang'e-4 lander and Yutu-2 lunar rover, which are performing missions on the far side of the moon, are in good condition. Among them, the Yutu-2 lunar rover is dormant on the 41st moon night, with a cumulative mileage of 1142.387 meters.

On Mars, the Zhurong rover has traveled more than 1.9 kilometers, and the Tianwen-1 orbiter is also carrying out orbital exploration around Mars, and will soon achieve global coverage of Mars. At present, the two devices are in good condition, and a large amount of scientific detection data has been obtained.

Our own Tianshanggongque, the Chinese space station, will also complete its on-orbit construction this year. The combination of the Tianhe core module and the Tianzhou-3 cargo spacecraft currently in space is in normal condition and the on-orbit operating parameters are stable.

Yutu-2 is a lunar rover for the Chang'e-4 mission. It separated from the Chang'e-4 lander at 22:22 on January 3, 2019, and arrived at the back of the moon. The first landing on the back of the moon has become another milestone in the development of China's aerospace industry.

微信8.0.22android测试版

下载地址（微信中打开）：

http://support.weixin.qq.com/cgi-bin/mmsupport-bin/readtemplate?t=page/android_exp__index
建议，收藏到微信中，这样下次随时打开，下载最新体验安装包。

安装体验版本聊天数据不会丢失。若体验不好，官网下载正式版覆盖安装即可。

Luo Junjie, spokesman for the Ministry of Industry and Information Technology, said at the meeting that we will moderately speed up the development of domestic resources, and work with relevant departments to resolutely crack down on unfair competition such as hoarding and price gouging, and promote the return of new energy vehicle raw material prices to rationality as soon as possible. Give full play to the role of a smooth and coordinated platform for the supply chain of the automobile industry chain, and strive to ensure the production and supply of parts and components. We should also pay attention to strengthening the overall arrangement of resources, and resolutely curb blind investment and duplication of construction.

Luo Junjie also said that, from a comprehensive perspective, my country's new energy vehicle industry has entered a new stage of large-scale and rapid development, and it is expected that it will maintain a rapid development trend this year. We will study and clarify support policies such as the continuation of car purchase tax incentives as soon as possible, and optimize the "double points" management method. According to the requirements of the "1+N" policy system of the dual carbon goals, organize the compilation of a low-carbon development roadmap for the automobile industry and provide guidance for industry enterprises.

In addition, Luo Junjie said that we will continue to carry out the pilot work of new energy vehicles to the countryside and the battery swap mode, and start the pilot city of full electrification of public vehicles. We will work with relevant departments to accelerate the construction of charging and swapping facilities, promote information sharing and unified settlement, and continuously improve the convenience of charging and swapping.

4 月 18 日消息，据 Google 中国官方账号「谷歌营销商学院」宣布，Google Ads 正式上线支付宝付款功能，无论是个人账户还是公司账户，现在都能用支付宝付款。目前只支持人民币结算，不支持美元及其他币种结算。

Google Ads 是 Google 开发的广告服务产品，广告客户可以在其中通过竞价向网络用户展示产品、服务或视频等。它可以将广告展示在 Google 搜索的结果中，也可以展示在非搜索网站、移动应用和 YouTube 视频中。

公布的官方流程，中国商家现在只需按照以下简单几步，即可开启新上线的 Google Ads 支付宝支付功能：

结算便利了，起底是100美元，有收入才是王道。