为什么Were you.回答却是yes,I was?

为什么Were you.回答却是yes,I was? yes,i were 还是 was.为什么 Were you here yesterday?Yes,i（ ） am、was、were? Were you busy last evening?A Yes,I were.B Yes,I was. Could you play when you were five years old?肯定回答是Yes,I could Do you like to do sth?为什么回答是Yes ,I do.不是Yes,I like. Do you like salad?回答为什么是yes,I like.而不是 yes ,I do. Do you like sausages?回答为什么是yes,I do.而不是yes,I like.,说明理由! Were you a pianist?Yes,I was.为什么问要用were?不是单数应该用was吗?为什么答的又用回 If I were you 中为什么是were而不是am或was Yes I do.Do you like biscuits?Yes I do 为什么回答的是I do,不是I like, 为什么是if only I were you 而不是if only i was you