肾虚腰痛,无明显阴阳偏盛者,可服用()
A.河车大造丸
B.补髓丹
C.六味地黄丸
D.青娥丸
E.金匮肾气丸
参考答案:D
— Did you know any Chinese before you arrived in Beijing?
— Never ________ it, actually.
A.had I learned
B.have I learned
C.I have learned
D.I had learned
对流层和平流层航空器的飞行环境是对流层和()。