We cannot do everything at once, but we can do something at once.
I believe everything has a solution, and I take it one day at a time or one thing at a time.
Experience teaches us only one thing at a time - and hardly that, in my case.
Work on one thing at a time until finished.
I've always been the sort of guy who's happiest doing more than one thing at a time.
Usually, whatever's in front of me is what I'm focused on and it's 100% on that and then I kind of move from one thing to the next. Like, if I go to a restaurant and I order food, I always just eat one thing at a time.