Looking on the internet deeply has found these results:

I will do what is I can do is the most popular phrase on the web.

I do what is I can do 112,730,000,000 results on the web	I will do what is I can do 113,610,000,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Puzzles is what I do, it's all I can do. Well, I'm not the Feds. I can't break into Peter Fleming's penthouse every night and can't hack the Ark computers, but what I can do is what I'm trained to do. What I can do is what I could always do: study the opposition, learn their habits, identify their weaknesses, and then share those things with my players. That I can't do, but what I can do is make it easier on Ms. Poplin. What I do is the best I can do.	It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

I do what is I can do

112,730,000,000 results on the web

I will do what is I can do

113,610,000,000 results on the web

More popular!

Puzzles is what I do, it's all I can do.
Well, I'm not the Feds. I can't break into Peter Fleming's penthouse every night and can't hack the Ark computers, but what I can do is what I'm trained to do.
What I can do is what I could always do: study the opposition, learn their habits, identify their weaknesses, and then share those things with my players.
That I can't do, but what I can do is make it easier on Ms. Poplin.
What I do is the best I can do.

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.