After a thorough investigation the police came to a conclusion that the car accident had resulted from drunk driving.
本题考查常见动词、名词短语及定语从句的使用。
彻底的调查：a thorough investigation；得出结论：come to a conclusion；由...造成：result from...；酒驾：drunk driving。
句子结构：主干为“警察（经过彻底调查后）得出结论”，“这起车祸是酒后驾车造成的”是定语从句。
