在“乃知圣人止有三法，无第四法也”中，“止”之义为（）
A.停住
B.只
C.同"之"
D.同"趾"
参考答案：B
在开采煤层群时，如果矿井瓦斯涌出量主要来自邻近层，则可由开采层向一定距离的顶（底）板其它煤层中打钻抽放，这种方法叫（）。
Which of the following statements about a monopolist is least accurate（）
A. The monopolist faces a downward sloping demand curve.
B. Unlike an oligopolist, a monopolist will always be able to earn economic profit.
C. A profit-maximizing monopolist will expand output until marginal revenue equals marginal cost.
