有一车祸患者,在事故中伤及腹部,被送到急诊室,行腹腔穿刺时抽出不凝固血液,应考虑为
A.腹膜后血肿
B.实质脏器破裂
C.空腔脏器破裂
D.前腹壁血肿
E.误入血管
参考答案:B
Hay farmers are in a perfectly competitive market. Assume that each acre of land produces 100 bushels of hay. The marginal revenue product of an acre of land is then:()
A. (price of hay per bushel)/100.
B. price of hay per bushel.
C. 100 × (price of hay per bushel).
某电容器额定耐压值为450伏,能否把它接在交流380伏的电源上使用?为什么?