能引起较严重贫血的疟疾是（）
A.间日疟
B.三日疟
C.卵形疟
D.恶性疟
E.输血后疟疾
参考答案：D
— Wow! You've got so many clothes.
— But ________ of them are in fashion now. [ ]
A. all
B. both
C. neither
D. none
如图，两人对拉质量为m=50Kg 的小车，F1=300N，F2=100N，小车加速度的方向______，加速度的大小______．
both