Printing specific items out of a list

I'm wondering how to print specific items from a list e.g. given:

li = [1,2,3,4]

I want to print just the 3^rd and 4^th within a loop and I have been trying to use some kind of for-loop like the following:

for i in range (li(3,4)):
    print (li[i])

However I'm Getting all kinds of error such as:

TypeError: list indices must be integers, not tuple.
TypeError: list object is not callable

I've been trying to change () for [] and been shuffling the words around to see if it would work but it hasn't so far.