Надо раскрыть скобки, поставив глаголы в правильную форму. 1)if ) coffee in the evening, ) sleep badly. 2) the days(get) longer if you(travel) north. 3) if you(press) this key, the display(light) up. 4) if you(book) you holiday in advance, you(get) a discount. 5) if jack(not eat), he(get) angry. 6)if you(heat) wax, it(melt).