疟原虫的终宿主是（）
A.人
B.牛
C.马
D.雌性按蚊
E.白蛉
参考答案：D
WD-400型电铲直流220伏励磁电压低的原因之一是三相桥式整流二极管有一个断路。
—What's Meimei doing?
—She _ _the piano. [ ]
A. plays
B. playing
C. play
D. is playing
