These fast-growing businesses are headed in exactly the right direction.The new bull market has given many people a renewed interest in investing. While fast-rising share prices may have you nervous about buying in at the wrong time, you can find great businesses in any market environment, especially if you invest with a long-term mindset.If you're on the hunt for compelling businesses that look like attractive investments right now, here are two top stocks to consider for your portfolio.1. DuolingoDuolingo ...