团体旅客乘坐火车旅行，必须在开车（）小时以前办理退票手续。
A、2
B、12
C、24
D、48
参考答案：D
______ , he could not carry the rock to the other side of the river.
A．Strong while he was
B．No matter how strong he was
C．As strong he was
D．However he was strong
出入境关系人因故撤销检验检疫时，检验检疫机构未实施检验检疫的，按收费标准的50%收费；已实施检验检疫的，按收费标准的100%收费。（）
