Dad: OK, Trevor, onions do we need? Trevor: Um, just one onion, I think. Dad: Very good. And cheese? Trevor: Mum said about 100g cheese. Dad: 100g .. fine. Now, tomatoes, Trevor? Trevor: We need ten tomatoes. Dad: What about spaghetti? spaghetti do we need? Trevor: We don't need to buy any. We have some at home. Dad: Right. The last thing is meat. meat do we need? Trevor: Meat? Oh, 500g! That's 500g beef.