“There are two windows in this room.”中为什么用in,不用of?

there are some 还是there are two there are two bears o-- there 英文翻译：There are same two.和 There are fifty. there are two kinds of memory there are two chairs and a desk There are two farmers ( ) the apple trees There are two pictures ) the wall Are there d_ between the two pictures? There are four windows ( )the two doors. there are two maps on the back there are two p______ of good news. are two there policemen 连词成句 There are two in number.是什么意思? There are some () between the two student There are two baskets of apples There are two t__students in our school. 1.There are about two t______ trees. There are two Japanese.改成单数形式