When is your brother's birthday和When was your brother's birthday

问题描述:

When is your brother's birthday和When was your brother's birthday
问生日一般用前者提问还是用后者提问?

一般用前者问.如果知道他刚刚过了生日,可以用後者.  有一道选择题,
  When ____your brother's birthday
  答案有is和was,我认为选前者好,为什么大家都选后者?When ____your brother's birthday是原题有上下文吗?没有的话你是对的,他们都错了。