是The ducks are swimming on the river 还是in the river?是There a

是The ducks are swimming on the river 还是in the river?是There a there are some ducks in the river are ducks any in river there the(?) There are teo ducks and a boat on the river. 是there is a boat in the river还是there is a boat on the river The ducks are swimming in the river.为什么用介词in,而不用on （ ）There are many ducks ____ the river.A.in B.on C.over some ( )are swimming in the river是fish还是fishes there is a small river ____ the hill.Six ducks are swimming （There are some ducks ）in the river.划线提问 英语句子这两个句子那个是对的呀?There are some ducks on the river.There are there is a river in the picture.there are some ducks and a b