一电阻两端的电压从2V增加到4V时，通过它的电流增加了1A，该导体的电阻为 Ω。
2
睾丸肿瘤的临床特点为：
A．血栓性浅静脉炎B．血栓性深静脉炎C．游走性浅静脉炎D．血栓闭塞性脉管炎E．动脉硬化闭塞症
—Wow, your new car looks so cool!
—Thank you very much! I _____ it for two weeks.
A．have had
B．have bought
C．bought
D．buy
