虚金本位制是指( )。
A．金银复本位制
B．银本位制
C．金币本位制
D．金块本位制
参考答案：D
With good treatment and care, Professor Smith unbelievably __________ from a heart attack in a week.
A．remained
B．returned
C．recovered
D．removed
蒸汽、内燃机车在电气化区段回送时应注意哪些？
