途切れる・切れる
The call cut off.
電話が切れました
The call cut off suddenly.
電話が突然切れました
The call cut off suddenly in the middle of talking.
通話中に電話が突然切れました
The call cut off suddenly in the middle of talking on the subway.
地下鉄で通話中に電話が突然切れました
The call cut off suddenly in the middle of talking on the subway this morning.
今朝地下鉄で通話中に電話が突然切れました