you can't do____(everything还是anything) your friends ask you to do,You'd better think first

you can't do____(everything还是anything) your friends ask you to do,You'd better think first

填everything.
not anything=nothing
例如：
I know nothing about the matter.
对于这件事我一无所知.
not everything“不是所有的事”,是部分否定.
I know somthing about the matter but not everything.
对于这件事,我知道点,但不是所有.