Well-known scenario.
Child (or grown-up for that matter) drops something. It breaks. It wasn't his/her fault! Oh, no! Well, whose fault was it? The cat's usually!
So it shouldn't be difficult to learn (and useful to know and use):

φέρω		I carry
πταίω		I stumble
καταβάλλω		I drop
θραύω		I break
οἴμοι		alas!

Think of the actual happening when saying the word for it. Don't think exclusively of the translation!
It is not just πταίω = I stumble and I stumble = πταίω, but πταίω and I stumble both refer to what happens when you don't look where you put your feet. Relate to reality when learning new words! Attach the new Greek word not only to the English one, but also to reality - use your memories: what your eyes see, your ears hear, your mouth tastes, your noise smells.... as well as what the lefthand side of your brain, concerned with abstractions (words are symbols, symbols are abstractions). The more connections you make - including to your English words - the more enjoyable and therefore easier your learning. And the better your recall.