若不论k为何值，直线y=k(x-2)+b与曲线x²-y²=1总有公共点，则b的取值范围是（　　）

如图是A、B、C三种固体物质的溶解度曲线，下列说法正确的是（   ）

选词填空。

    Deng Feng is my friend．He is____and interested in music．He usually gets up at 6：00 in the morning and then he does some____in the park．He likes to listen to____music When exercising．Before going to bed，he listens to some____of light music．Sometimes he'd like to enjoy traditional Chinese music．He____it's a good way to relax．Some day,he will study music and be a musician．

以下活动需要能量最少的是（　　）