The reason is " serious brain drain", "high layer upon layer" and "the difficulties of access";

其原因主要是“流失严重”、“层层拔高”和“进入困难”；

youdao

The reason is " serious brain drain", "high layer upon layer" and "the difficulties of access";

其原因主要是“流失严重”、“层层拔高”和“进入困难”；

youdao