签约企业网上银行后，为客户选择角色和可操作账号，还须为客户至少增加（）个企业网上银行操作员。
A.1
B.2
C.3
D.4
参考答案：B
完成下列单位换算：（1）5.2×104mg=______kg；（2）3.2×1027t=______kg
—Whose purple coat is this?
—It ____ be Lily’s. Hers is red. It _____ be Lucy’s. She likes purple.
A．must; may
B．may; must
C．can’t; may
D．mustn’t; must
