为检查角膜上皮是否有损伤，可用荧光素钠染色后再检查，荧光素钠的浓度应为（）
A.0.5％
B.1％
C.2％
D.3％
E.5％
参考答案：C
Did you ask whose computer ______________ ?
A．that blue one was
B．is that blue one
C．it was that blue one
D．that blue one is
梁抗弯截面系数与材料的性质（）
