英语翻译那为什么用were不用was?

英语翻译那为什么用were不用was? If I were a bird的英语语法问题?为什么用were 不用was?那如果我用was又是什么意思？ If today were the last day.那句话中为什么用were,而不用was.求高人指点 how was their holiday 为什么用was而不用were How was your holiday?为什么用was 不用were were 和 wes的用法为什么在When were you born?用were而不用was为什么when was your brother born?用was而不用were That proud woman acts as though she were above us这里为什么用were不用 was? if i were a boy again为什么用were而不用was If I were a boy中,为什么要用were不用was? Susan is walking slowly as if she were tired问:为什么用were而不用was if I were a boy为什么要用were不用was?求解 I thought you were be taller.这里为什么不用was,而用were?求用法 If you were me ,what would you do 为什么用were 而不用was? 为什么 if i were a boy 中的were 不用was? 为什么If only I were abird.中的were不用was when was your last trip?这个地方为什么不用were用was noby except the men was left behind为什么用was,不用were There was not_( be not )any bread at home yesterday.为什么用WAS不用WERE