It _______ seven years __________ Hong Kongreturned to China.

He didn’t come to the meeting yesterday.That was _____he had to see his sister off at the airport.[ ]

There are some warnings in some countries ______ over exploitation of underground water has caused the decline of wetland and increase of desertification.

We plan to have a meeting ______ theafternoon ______ October 10th.

依次填人下列各句横线处的成语，最恰当的一组是（ ）①奥巴马将与冒险家贝尔．格瑞斯一起，在阿拉斯加州荒野__________体验野外生存，并将会见几位专家了解地区气候变暖的情况。②《纳赛尔丁阿凡提传》中的阿凡提始终都是一个行侠仗义、好打抱不平的侠士，他_____，四处流浪，是路人甲乙丙丁中的一个。③陆羽，为了搜集《茶经》的资料游历天下，一路上，他________，日晒雨琳，足迹遍布巴山蜀水、荆楚大地、吴越山川等地。