使用“迅雷”可以下載，官網下載頁面：
https://download.qt.io/official_releases/qt/5.12/5.12.0/
Windows:
http://iso.mirrors.ustc.edu.cn/qtproject/archive/qt/5.12/5.12.0/qt-opensource-windows-x86-5.12.0.exe
Mac:
https://download.qt.io/official_releases/qt/5.12/5.12.0/qt-opensource-mac-x64-5.12.0.dmg
Linux:
https://download.qt.io/official_releases/qt/5.12/5.12.0/qt-opensource-linux-x64-5.12.0.run
