(7)may可变成might.（11）不变，因为是客观事实.（13）嗯，所以不用变.（16）Her mum told her she must study hard for her English.(21)She asked me whether she was my English teacher.(22)Tom asked whether Jim studied hard.(23)My mom asked us whether we had seen the film.(37)He told us to play football the next day....
11因为出生是过去时，不牵扯到其他的，肯定过去13 every morning是一般现在时标志，如果要过去的话，last morning应该更好16 没什么悬念，must +动原21 没什么悬念的，其实is she your English teacher会更简单22也没什么悬念，就是一般现在时加上反问，与一般疑问相同，语气更强而已...
