装饰性涂装可分为高级、中级和一般装饰性涂装。
参考答案：对
结构为3-甲基十五环酮的是
A．精氨酸 B．强心甾烯 C．麝香酮D．蟾蜍甾二烯 E．鹅去氧胆酸
—Why did you stop the car?
—I'm afraid we ______ the gas. [ ]
A. are using
B. have filled up
C. broke down
D. have run out of
