坞龄超过（）年的浮船坞，构成主体结构一部分的燃油舱应进行内部检查。
A、1
B、5
C、10
D、15
参考答案：D
It is said that a grave of a middle aged man () about 2,300 BC was found by some English archaeologists in the year of 2002.
A．dating back
B．dated back to
C．dating back to
D．dated from
国际单位制的国际通用符号是SI，来源于法文。
