house是单数吗为什么in their house不加s

in their house house为什么不加s 为什么in their opinion中的opinion不加s? The house smells of paint.smell 为什么加s? I have just moved to a house in bridge street.这句话里in 后面为什么不加 为什么"Where did you live?"的后面不加in,而"What house did you live 后面 On Christmas Day,they were in their grandparent's house修改病句 为什么单数加s而复数不加s in the house Kula in the house our love in the house sweet s describe a city that you live in 为什么describe不加s?动词单数 是说in Marry's house,还是in the Marry's house（Marry人名）,请说明理由 第三人称单数怎么写,比如PLAY的第三人称单数是PLAYS,为什么加S怎么不加ES? at a dumpling house,in a noodle house,中at 与 in 是固定的吗?