高中物理奥赛:There was/ were a group of wolves. Was or were? Y?

There was/ were a group of wolves. Was or were? Y? There was no wind and the trees were still. 请教~~关于was/were和did Everyone expect Tom and John was there when the meeting began.中的was为何不能用were? Yes .You see ,I was making a face .There was a hat on my head while there were no shoes on my foot 是WERE还是WAS? 翻译:Long ago,there was a big cat in the house.He caught many mice while they were stealing food. Everyone except Bill and Jim__ there when the meeting began.A.was B.is C.are D.were There were , too,many children there.是什么意思? There were too many children there .是什么意思?