You don't have to USE them all immediately. That's not the way one uses a language, be it a child or an adult. First, you hear / learn the word. Eventually, you come to understand the word. Later, you come to be able to use it.
It's a long process, but that's the natural language-acquisition process. Of course, you can give the process a boost thru intensive studying, but you cannot really subvert the process.
So, don't worry if you can't use them. If and when you read them, you'll know the definition, and if and when you need to use them, they might pop up in your mind, or you might use a thesaurus to recall them.
Good luck with your next test. Study plenty, be confident, and let your confidence shine through and carry you through.