This is going to be silly but I know some people who don't really leave the house for anything but groceries. It's impossible to hang out with them because they just sit around at home and the only thing they leave the house for are groceries. Today I told a friend about them and said
all they do is getting groceries
and would like to know if it's right to use the continuous form.
Other sentences that follow the same pattern:
All they can do is cut/cutting them down
All he/she is able to do is yell/yelling at people
I think you guys get the picture.