Why isn't the last one "the cat likes to drink." Isn't milk modifying drink?

Through this exercise I found that being able to identify the concession makes the conclusion to the argument much easier to quickly identify.

It seems that understanding assumptions ONLY in the context of the argument is important. Assumptions are only aspects of the arguments that are not explicitly stated. The reason the tiger being a mammal is an assumption is because it is not explicitly said to be a mammal in the passage.