在固定汇率制下，一国货币对他国货币的汇率基本固定，只在一定范围内波动。（）
参考答案：对
—Must I do my homework now? Mum.
—No, you _____.You can do it after supper.[ ]
A. can't
B. needn't
C. mustn't
D. don't
_______ her parents were strongly against it, she married the young man.
A．For
B．If
C．Since
D．While
