Thank one's lucky stars: o que isso significa?

Imagine you're attending a test tomorrow and you decide to go over some of the topics you think might be on the test. You haven't actually touched your books up to this point and now you're trying to make it up by burning the midnight oil, that is to say, you're studying late into the night. The next morning, while you're doing your test, you see that the hours you spent last night studying really paid off. You were lucky enough to have studied the right things for the test. You knew the answer to all the questions as if you'd been studying in months, when actually you just spent one night studying. When you're done with the test, you can't wait to find your classmates to tell them what just happened. When you finally see one of them, you say: I thank my lucky stars that I studied the right things for the test.

When you thank your lucky stars, you're grateful you've avoided an unpleasant situation. You had all the odds against you, but then thank your lucky stars, you turned out fine. Suppose your classmates didn't have the same kind of luck as you and when they find out about your success, they think it's unfair. Here's what they say: You can thank your lucky stars now that you've avoided failing this class. That's all for today guys. See you around!