是two hind of 还是 two kinds of对

是two hind of 还是 two kinds of对 two kinds of dog 还是 two kinds of dogs? two kinds of fishes two kinds of 两种鱼two kinds of+fish还是+fishes啊! two kinds of+pl.还是——单数名词? two boxes of apple 还是 two boxes of apples对? 两串钥匙是two set of keys还是two sets of keys,哪个对?为什么? two different kinds of traffic 翻译 compare two kinds of sports中文翻译 there are two kinds of memory 英语语法问题两条鱼英语是two fish,也可以是two fishes,两种鱼,英语是two kinds of fish