可引起射血分数增大的因素是
A．心室舒张末期容积增大
B．动脉血压升高
C．心率减慢
D．心肌收缩能力增强
E．快速射血相缩短
参考答案：D
Jim is outside the room. Please open the door and ___________.[ ]
A. let him in
B. let in him
C. let him out
D. let out him
激流回旋比赛时逆水门可以是几个（）
A.7个
B.8个
C.9个
D.10个
