{{pbrtbook-main.rar(uploading...)}}

建议安装新版本

C:\Users\Administrator>tlmgr update --self --all --reinstall-forcibly-removed
TeX Live 2021 is frozen
and will no longer be routinely updated.  This happens when a new
release is made, or will be made shortly.

If you're willing to help with pretesting a new release, and we hope
you are, please see https://tug.org/texlive/pretest.html.

For general status information about TeX Live, see its home page:
https://tug.org/texlive

\CTEXsetup[name={,},number={\arabic{section}}]{section}

bm only inspects the ‘top level’ definition of a command, for more complicated
expressions, and anything inside a { } group, bm forces bold fonts by essentially
the same (slow) technique used by the AMS boldsymbol command (but bm still
takes more care of the spacing).