what were Ted and his sister doing?
Ted and his sister正在做什么?
因为正对2天前这个时间段在干么
所以回答就是他们在听收音机为什么有人说这个是正确的？——When did Ted and his sisterlisten to the radio ?They left for Beijing (two days ago)对括号里词进行提问when did they leave for Beijing?一样的意思,这句话就是他们什么时候离开去北京的，回答就是2天前或许我理解错了 就是问他们在什么时间段听收音机的！所以正好针对at this time two days ago 也就是在2天前这个时间段 他们在听收音机！