违约频率是指借款人在未来一定时期内发生违约的可能性。( )
参考答案：错
------Is Catherine seriously ill?
------ ____________. She is in hospital and remains unconscious.
A．I don’t think so
B．I’m not sure
C．I’m afraid so
D．I hope not
全部免疫活性细胞均来源于
A．树突状细胞B．单核巨噬细胞C．骨髓多能干细胞D．胚胎多能干细胞E．淋巴干细胞
