单选题 In recent years there has been a strong______toward the "open classroom" in the elementary schools of the United States.
【正确答案】 D
【答案解析】解析：句意：最近几年，在美国小学中有一种开放课堂的趋势。tendency倾向，趋势。assumption假定，臆断。transition过渡，转变。bent倾向；爱好。