艾滋病的各种感染主要在
A．肺、胃肠与神经系统B．肾脏C．血液系统D．皮肤E．心脏
参考答案：A
______ both of us failed to pass the driving test, ______ we learned much about driving. [ ]
A. Unless / and
B. Because / 不填
C. Though / but
D. Although / 不填
活塞式压缩机身产生异常响声原因有哪些？如何处理？
