现有木炭、一氧化碳、氧化铜、氧化铁、稀硫酸五种物质，它们之间发生的反应，可用“A+B→C+D”表示． （1）若A为单质，A与B在高温下反应，可观察到
2013年5月25日，“与中国梦同行”2013阳光少年文化节在北京启动。本次文化节营造了浓厚的文化氛围，陶冶了情操。这体现的文化生活道理是 A.文化对
The foreigner tried his best, but he still couldn’t make his point ____ . A. understand B. understanding C. to understand D. understood
空气中含量最多的物质是 A. 氧气 B. 氮气 C. 二氧化碳 D. 稀有气体
Don’t you know that the famous university is as a matter of fact ______ used to be a church? A. where B. what C. which
Self-esteem(自尊心) is all about how much we are valued, loved, accepted, and thought well of by others and how much we value, love and accept ourselves. People with healthy self-esteem are able to
的最大值和最小值。 
，
，
，当
；当
时，
。