集存款、取款、贷款、消费、结算、查询为一体的信用工具是 [ ]
A.支票
B.汇票
C.信用卡
D.电子货币
答案:C
I won’t tell the student the answer to the math problem until he ________ on it for more than an hour.
A.has been working
B.will have worked
C.will have been working
D.had worked
董事、经理违反《中华人民共和国公司法》第六十条的规定,以公司资产为本公司的股东或者其他个人债务提供担保的,担保合同是否有效?