单选题Traffic restrictions have&nbsp

问题补充：

单选题TrafficrestrictionshavecomeintoeffectinBeijingtoimprovethecapital’sairqualityandtrafficsituationfortheOlympics．A.in order thatB.in an attemptC.at an attemptD.in a try

答案：

B解析in an attempt to do sth努力尝试做某事。