为什么不能用were?

为什么不能用were? where were you do last sunday?这里为什么不能用were,而用did at least 21 people were killed and 174 others【 injuered 】after .为什么不能用were hurt The boys were singing while the girls were dancing last night.为什么用were singing.不能用sang吗? ___ ___Red Cross,many people were saved in the war.为什么不能用because of? there were no more mountains in sight 我想不通为什么用no 不能用not when the guest arrived.we were having our supper.为什么不能用as soon as连接 我是昨天问你英语的网友为什么第一句不能用were The injured men were sent to a nearby hospital .为什么不能用near? many people(being)absent,the meeting had to be put off为什么不能用were? We were very much surprised .这句话为什么不能用very much 当后缀? How long did you sleep为什么用did ,不能用were you sleeping 或 asleep. There (was) some interesting news in yesterday's newspaper.请问为什么不能用were? _ data were obtained would beprocessed by a computer.为什么不能用Which _ data were obtained would be processedprocessed by a computer.为什么不能用What ___ food and medical instruments were provided by the government为什么不能用 the whole My legs were ( ) tired that I wanted to stop.为什么只能用so,而不能用too和very 为什么不能用了?