燃用高牌号汽油时，应将辛烷值选择器转向“+”侧。
参考答案：错
砌体工程的质量控制点为( )。
A．翻样图B．地基承载力C．放大样D．皮数杆
Which of the following condition is least likely to be the obstacle to the efficient allocation of productive resources:（）
A. Price controls
B. Taxes and trade restrictions
C. Perfect competition
