这个问题吧，起因在于要用pipenv命令，而不是pip命令，应用pipenv install package，就能够安装包并增加到PipFile中。
Courtesy Notice: Pipenv found itself running within a virtual environment, so it will automatically use that environment, instead of creating its own for any project. You can set PIPENV_IGNORE_VIRTUALENVS=1 to force pipenv to ignore that environment and create its own instead. You can set PIPENV_VERBOSITY=-1 to suppress this warning.Usage: pipenv [OPTIONS] COMMAND [ARGS]...Options: --where Output project home information. --venv Output virtualenv information. --py Output Python interpreter information. --envs Output Environment Variable options. --rm Remove the virtualenv. --bare Minimal output. --completion Output completion (to be executed by the shell). --man Display manpage. --support Output diagnostic information for use in GitHub issues. --site-packages / --no-site-packages Enable site-packages for the virtualenv. [env var: PIPENV_SITE_PACKAGES] --python TEXT Specify which version of Python virtualenv should use. --three / --two Use Python 3/2 when creating virtualenv. --clear Clears caches (pipenv, pip, and pip-tools). [env var: PIPENV_CLEAR] -v, --verbose Verbose mode. --pypi-mirror TEXT Specify a PyPI mirror. --version Show the version and exit. -h, --help Show this message and exit.Usage Examples: Create a new project using Python 3.7, specifically: $ pipenv --python 3.7 Remove project virtualenv (inferred from current directory): $ pipenv --rm Install all dependencies for a project (including dev): $ pipenv install --dev Create a lockfile containing pre-releases: $ pipenv lock --pre Show a graph of your installed dependencies: $ pipenv graph Check your installed dependencies for security vulnerabilities: $ pipenv check Install a local setup.py into your virtual environment/Pipfile: $ pipenv install -e . Use a lower-level pip command: $ pipenv run pip freezeCommands: check Checks for PyUp Safety security vulnerabilities and against PEP 508 markers provided in Pipfile. clean Uninstalls all packages not specified in Pipfile.lock. graph Displays currently-installed dependency graph information. install Installs provided packages and adds them to Pipfile, or (if no packages are given), installs all packages from Pipfile. lock Generates Pipfile.lock. open View a given module in your editor. run Spawns a command installed into the virtualenv. scripts Lists scripts in current environment config. shell Spawns a shell within the virtualenv. sync Installs all packages specified in Pipfile.lock. uninstall Uninstalls a provided package and removes it from Pipfile. update Runs lock, then sync.