Yeah, that's what I found difficult at first. There are so many frameworks out there that it is impossible to 'know everything'. The key is to find a general area in which you want to work, pick up a popular framework in it and just get to cranking out applications. If they ask you whether or not you know their particular stack, you can answer something along the lines of, I'm a very quick learner, and I might not know all aspects of your stack, but I can pick it up quickly. The key is not to be a 'framework' or 'features' master, aka memorizing every single method of frameworks, but the key is to get working things out there and demonstrate that you are willing to learn and can do so quickly.