The ship’s generator broke down and the pumps（）(不得不用手工操作) instead of mechanically.

It may be necessary to stop（）(每隔一定时间) in the learning process and go back to the difficult points in the lessons. 点击查看答案

There’s a man at the reception desk who seems very angry and I think he means（）(想找麻烦). 点击查看答案