想問以下幾題英文題

要用以下幾個字做...

in front of
behind
oppsite
by
under
on
in
at

1. Fred, June and Rose are riding _____ the dinosaur train.
要講佢地坐緊train...


2. He is ____ the big dinosaur.
係dinosaur 隔離

3. Marco and Ann are___ the pond.
佢地企係個pond 周圍