python安装虚拟环境virtualenv出错，崩溃！求大神指点

控制台输入pip install virtualenv

E:\>pip install virtualenv
Requirement already satisfied: virtualenv in d:\python38\lib\site-packages (20.0.4)
Requirement already satisfied: filelock<4,>=3.0.0 in d:\python38\lib\site-packages (from virtualenv) (3.0.12)
Requirement already satisfied: appdirs<2,>=1.4.3 in d:\python38\lib\site-packages (from virtualenv) (1.4.3)
Requirement already satisfied: six<2,>=1.9.0 in d:\python38\lib\site-packages (from virtualenv) (1.14.0)
Requirement already satisfied: distlib<1,>=0.3.0 in d:\python38\lib\site-packages (from virtualenv) (0.3.0)

这是什么情况？
因为没有报错，我尝试搭建flask虚拟环境，继续操作如下：

E:\>cd env_1

E:\env_1>virtualenv flask
created virtual environment in 2296ms CPython3Windows(dest=E:\env_1\flask, clear=False, global=False) with seeder FromAppData pip=latest setuptools=latest wheel=latest app_data_dir=C:\Users\86181\AppData\Local\pypa\virtualenv\seed-v1 via=copy

E:\env_1>

能够看到创建的文件夹

继续控制台命令输出：

 E:\env_1\flask\Scripts 的目录

2020/02/15  18:39    <DIR>          .
2020/02/15  18:39    <DIR>          ..
2020/02/15  18:39             2,291 activate
2020/02/15  18:39               892 activate.bat
2020/02/15  18:39             3,157 activate.fish
2020/02/15  18:39             1,815 activate.ps1
2020/02/15  18:39             1,194 activate.xsh
2020/02/15  18:39             1,225 activate_this.py
...
...

E:\env_1\flask\Scripts>activate
E:\env_1\flask\Scripts>

所期待的 E:\env_1\flask\Scripts> 前缀 (flask)居然没有…

到底哪里出问题了呢?我怎么才能得到我想要的

 (flask)E:\env_1\flask\Scripts>

求大神指点