nurses have to work night shifts from time to time

nurses have to work night shifts from time to time from time to time Nurses have to work ___ night.A.in B.on C.at We have to rest from time to time.意思 We have to rest from time to time.是什么意思 have three shifts this week,but i will have normal work time 英译汉：from time to time The hospital was very busy.The nurses did not have time to t time to work I came here right from work.I didn't have time to stop by my She has to work on weekends from time to time.怎样改成含有sometime have much time to