重型地中海贫血患者应输注（）
A.新鲜全血
B.浓缩红细胞
C.机采血小板
D.冰冻红细胞
E.冷沉淀物
参考答案：B
空气呼吸器每次使用后要对（）等组件进行清洁、消毒。
A、全面罩
B、背托
C、气瓶
D、减压阀
E、供气阀
During the day，a dredge will indicate the side on which it is safe to pass by displaying（）.
A.two balls in a vertical line
B.two diamonds in a vertical line
C.a single black ball
D.no shape is shown during the day
