从外表看,二极管正、负极管并无区别,为了不致搞错,出厂时用不同颜色的油漆涂在顶上作记号,()涂蓝色或黑色,使用时必须注意。
A、正极管
B、负极管
参考答案:B
I had ______ feeling of happiness when I heard that he had made ______ great progress.
A.a; a
B.the; a
C.the; 不填
D.a; 不填
清胃散中体现"火郁发之"之意的药物为()
A.升麻
B.丹皮
C.黄连
D.当归
E.生地