皮质性白内障（如图）的混浊常表现为（）
A.棒状
B.楔形
C.点状
D.块状
E.哑铃状
参考答案：B
促进红细胞成熟的因素有（）
A.肝素
B.叶酸
C.维生素B12
D.雄激素
E.内因子和维生素B12
We drove to the airport to meet an expert from Germany, about 50 years old, his hair ________.
A．was completely grey
B．be completely grey
C．to be completely grey
D．completely grey
