求最大公约数时依然使用重复带余数除法，直到余数为（）时为止。
A.0
B.1
C.2
D.3
参考答案：A
A fixed income portfolio manager is evaluating investments in the mortgage market but is concerned about prepayment risk. The security that will most likely minimize prepayment risk is.（）
A. mortgage passthrough security.
B. a portfolio of interest-only mortgage loans.
C. tranche B of a collateralized mortgage obligation.
人体软组织中的声速接近（）
A.3600m／s
B.1540m／s
C.1860m／s
D.1450m／s
E.2000m／s
