键码的定义：在实体集的范围内惟一标识 ______ 。
参考答案：实体
骨髓纤维化尤其要注意与下列哪种疾病加以鉴别（）
A.CML
B.CLL
C.急性白血病
D.多发性骨髓瘤
E.恶性淋巴瘤
When a person dies, his debts must be paid before his ______ can be distributed.
A．paradoxes
B．legacies
C．platitudes
D．analogies
