题目

By the time he arrived at the airport, he found his flight _________.A. take off B. took off C. has taken off D. had taken off 答案：【答案】D【解析】句意：当他到达机场时，他发现了他的飞机已经起飞了。A. take off 起飞，一般现在时；B. took off起飞，一般过去时； C. has taken off已经起飞，现在完成时；D. had taken off已经起飞，过去完成时。从句By the time he arrived at the airport是一般过去时，“飞机起飞”发生在“到达机场”之前，即“Those flowers were 　　　　 for your mother on her seventieth birthday， but as she is away， I would be glad if you accept them. A. offered                     B. produced           C. meant              D. supplied