It was not known what caused the ship to sink and no distress call had been made, the center said.

目前还不清楚船下沉的原因，没有收到遇险信号，该中心表示。

youdao

Airline officials said they had no indication of why the plane went down - there was no distress call from the cockpit.

航空官员表示飞机失事原因不明，机舱没有求救电话。

youdao

"No one went to the aid of this boat, despite a distress call logged by the Italian Maritime Rescue Coordination Centre, which pinpointed the boat's position, " the report said.

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After the mother panda's distress call Sunday, a veterinarian examined the cub and observed that it was not breathing and had no heartbeat, said Suzan Murray, the zoo's chief veterinarian.

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