4.I __________ locked myself out of the house. A.accident, B.accidental, C. accidentally D./

― _____ An accident has happened. A. Where was the accident? B. What happened? C. When was the accident? D. Why did it happen?

这起事故必须仔细调查。译文：________________________________. A: The accident must investigated carefully B: The accident must be investigated carefully C: The accident must investigating D: The accident must be investigating

—————————— is not clear. A: what caused the accident B: what did cause the accident

There was a serious accident yesterday. Do you know which driver______ the accident?

The following are not part of the emergency rescue system ( ). A: accident plan decision B: traffic accident site treatment C: traffic accident detection and confirmation D: traffic investigation

If only the accident _____ !

fall by accident

They were late because there was an accident on the road. (强调原因）It was because there was an accident on the road ______ they were late.

Unfortunately, those who_____ the accident cannot recall what happened, Therefore the cause of the accident remains a mystery.