表达“必须"这个命令的口吻，是不是总想到用must，更地道的表达是have got to do, 简化为've got to do, 更口语化的是gotta. 例如拨打急救电话时说，我邻居受伤了，快叫救护车来，立刻马上！My neighbour's got injured, you've got to send an ambulance. Right now! 再如，我得走了 I gotta go