It's hard to say without the logic structure of your corollary, but it's usually possible to write something like:
Consider $\spadesuit$. From $A$ we can infer $\clubsuit$ and $B$ yields $\diamondsuit$. This allows us to do $\heartsuit$ which leads to $\blacksquare$ via $C$. Taking all this together allows us to formulate the following corollary:
Corollary 3.14: Lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum
If the results are similar enough, then you can combine them in a single result (already mentioned by @Ahmed in the comments). Personally I try to avoid such composites because these never feel clean enough for me. Still, I've seen such with hardly any drawback.
Yet another way is to formulate the corollary so that it is a direct result of $C$, that is, apply $A$ and $B$ in the premise. The disadvantage is that these might be clumsy, especially if $C$ is a rather minor step when compared to $A$ or $B$.
Finally, you could write an explanation or a proof sketch that would remove any doubt as to which results have been used. That sometimes is the best, but when the corollary is not really important it diverges attention and bloats the paper.
I hope this helps $\ddot\smile$