如图,在△ABC中,点D、点E分别在AB、BC边上,且DE∥AC,DE=2,AC=3,BE=4,则BC长度为____ .
化石燃料是我们当前生活的主要能量来源,关于化石燃料的说法正确的是( )
— Are you a fan of Zhou Libo?—Yes. Not only I but also my sister him very much.