如图所示，小露用电吹风从A端对着泡沫机翼模型送风，机翼升起，下列说法正确的是（  ）

下列课外实验中不涉及化学变化的是（　　）

    My teacher Mr. Li is a y____ man, about 25 years old. He is a h____ teacher, working(工作) at school from 7:30 in the morning to 18:30 in the e____. It seems(仿佛) that he has many things to do every day. Although he's b____ with his work and has no time to play, after class he likes playing f____ with boys in the playground. Look! He's kicking the ball! We all like him very much.

下列地形中，占我国面积比例最大的是（    ）

央视二套（这是真的吗？）栏目播出了电脑浸在液体中也能正常工作的新鲜事，这种液体可为手机电脑“洗澡”，用来清洗电子产品，它是被称作“绝缘液”的一氟二氯乙烷，结构如图，下列说法正确的是____

A、一氟二氯乙烷由两种元素组成

B、一氟二氯乙烷中碳元素与氢元素的质量比为1：3

C、一氟二氯乙烷的相对分子质量为117

D、一氟二氯乙烷____．