《中华人民共和国铁路法》于（）起施行。
参考答案：1991年5月1日
Which of the following sentences is NOT right?[ ]
A. There is no doubt that you will succeed.
B. We have no doubt that you will succeed.
C. We don't doubt that you will succeed.
D. We don't doubt whether you will succeed
我国1元硬币的直径大约是（ ）
A．2.5m
B．2.5dm
C．2.5cm
D．2.5mm
