一定质量的理想气体的状态变化过程如图所示，AB为一条直线，则气体从状态A到状态B的过程中（ ）
A．气体分子平均动能保持不变
B．气体分子平均动能先增大后减小到初始状态
C．整个过程中气体对外不做功
D．气体的密度在不断增大
A、pV=CT，C不变，pV越大，T越高．状态在（2，2）处温度最高．
在A和B状态，pV乘积相等，所以温度先升高，后又减小到初始温度，则气体分子平均动能先增大后减小到初始状态．故A错误B正确．
C、气体膨胀，则气体对外界做功，故C错误．
D、气体的体积在不断增大，质量一定，所以气体的密度在不断减小．故D错误．
故选：B．
It happened to a very young pastor (牧师).His church was very old and what's worse, a storm knocked a hole in the wall of the church. One day the pastor1_____an auction(拍卖）and bid a beautiful tablecloth for six dollars. Hecarried the cloth back to the church and put it up on the wall. It completely hid the 2_____! Just before noon of Christmas Eve, the pastor noticed a woman standing in the cold at the bus stop. “The 3 _____won’t be here for 40 minutes!” he called, and he invited her into the church to get 4_____ .She told him that she had come from the city to be interviewed for ajob as governess to the children of one wealthy family in town but she had been turned down. The woman saw the tablecloth and rose suddenly. The pastor smiled and started to tell her about the storm 5_____, but she didn’tseem to 6_____“It is mine!” she said. “My husband had the cloth made 7_____ for mc ! She explained that she and her husband decided to go separately in the War II. They planned that he would 8_____ her. But she never saw him again. Later she heard that he had died. The pastor tried to 9_____ her, advising her to take the cloth with her. She 10_____ . Then she went away. On Christmas Eve, after the service in church, one middle-aged man—the local clock-and-watch repairman—looked rather 11_____.‘‘It is strange，”he said in his soft accent. “ Many years ago, my wife and I owned such a cloth. The pastor suddenly became very 12_____ . He told him about the woman who had been in church 13_____ in the day.Together the two got in touch with the 14_____ who had interviewed her. And this man and his wife -who had been separated through so many saddened 15_____were reunited.
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