最高运行速度120km/h及以上的客车应装有电空制动机、盘形制动装置和防滑器,空气制动系统用风应与空气弹簧等其他装置用风分离。
参考答案:对
保和丸出自《丹溪心法》,由山楂、神曲、半夏、茯苓、陈皮、连翘、莱菔子组成。消食,导滞,和胃。用于食积停滞,脘腹胀满,嗳腐吞酸,不欲饮食。处方中山楂应选用()
A.生山楂
B.炒山楂
C.山楂炭
D.焦山楂
E.姜山楂
A group of scientists studying calcium metabolism in laboratory rats discovered that removing the rats’ parathyroid glands resulted in the rats’ having substantially lower than normal levels of calcium in their blood. This discovery led the scientists to hypothesize that the function of the parathyroid gland is to regulate the level of calcium in the blood by raising that level when if falls below the normal range. In a further experiment, the scientists removed not only the parathyroid gland but also the adrenal gland from rats. They made the surprising discovery that the level of calcium in the rats’ blood decreased much less sharply than when the parathyroid gland alone was removed. Which one of the following, if true, explains the surprising discovery in a way most consistent with the scientists’ hypothesis ?()
A.The adrenal gland acts to lower the level of calcium in the blood.
B.The adrenal gland and the parathyroid gland play the same role in regulating calcium blood levels.
C.The absence of a parathyroid gland causes the adrenal gland to increase the level of calcium in the blood.
D.If the adrenal gland, and no other gland, of a rat were removed, the rat’s calcium level would remain stable.
E.The only function of the parathyroid gland is to regulate the level of calcium in the blood.