【单选题】I don’t think ___ of his parents are home. They usually go out for a walk at the moment. [ ]
【判断题】If buyers expected the future price of a good to decrease, it would tend to increase the current quantity exchanged.
【简答题】The sellers are obliged to advise the Buyers of the expected date of shipment and the concrete quantity ready for shipment before the Buyers open letters of credit.
【单选题】液压泵的( )是在不考虑泄漏的情况下,单位时间内泵所输出的液体的体积。
【单选题】下列哪项不是引起B细胞介导的免疫应答水平下降的原因
【单选题】感染HIV后,下列哪项不是导致机体免疫功能受损的主要机制( )
A.
被感染的CD4+淋巴细胞表面表达gp120,可与其他CD4+细胞相互融合,细胞被破坏
C.
HIV感染B细胞,能使其大量破坏,抗体生成减少
E.
感染HIV后诱发机体的免疫反应,使受感染细胞受到攻击而被破坏