Hi! Congrats on the interview! I'd say go through the new literacy framework and for yr4, pick an objective and make it very specific, so they can see in your lesson you have taught the children something new. I'm in the same position myself but have to teach Yr6 poetry so it's a bit more defined. Try to choose a topic you've taught before or feel confident with. I'm also going to plan the next lesson so they can see the progression. Sorry if this had already been thought about! Good luck!