1. Time and weather have worn off the name on the gravestone.
   天长日久的风雨冲蚀了墓碑上的名字。
2. Blink your headlights on and off.
   使车前灯闪烁(打信号)吧。
3. She hopped on her bicycle and rushed off.
   她跳上自行车匆匆离去。
4. Make beds. Take sheets off and put new sheets on beds.
   铺床。撤去旧床单并换上干净的床单。
5. We have been dating on and off.
   我们断断续续在约会。

　1个副词解释