老师说in+大地点,at+小地点,但后来又说in the kitchen,想知道为什么～

老师说in+大地点,at+小地点,但后来又说in the kitchen,想知道为什么～ at the kitchen还是in the kitchen 小地方用at,大地方用in,为什么Lost and Found office是小地点,却用in? at the kitchen和in the kitchen都行吗 in the kitchen是什么意思 “ thing in the kitchen ”, I —(cook)in the kitchen at the moment look at the picture .Neil ______(sit)in the kitchen Don't look at books in the kitchen.(改错） Don't look at books in the kitchen.(改错) My parents ___food in the kitchen at that time do not look at books in the kitchen.怎么改