Question

I can see Hank that you are studying hard

Answer 1

There are a couple ways: I can see, Hank, that you are studying hard. (Or) Hank, I can see that you are studying hard.

Answer 2

There are several ways you can write this and still be grammatically correct. 
Hank, I see you are studying very hard.
I can see, Hank, that you are studying quite hard.
You are studying very diligently, Hank.