这件事是什么时候发生的

问答题当我们到达车站时，火车已开出了。

单项选择题二、完形填空

单项选择题Which of the following is the best title for the passage

单项选择题What cause the BMD loss to astronauts according to this passage

单项选择题Please paraphrase the clause your actions can speak louder than your words .