A:understood
B:understanding
C:to be understood
D:to understand
----You park here! Look at the sign, it says “No parking”.
----Sorry, I didn't notice that sign just now.
2010年7月3日一支科学考察队去某地考察,用手持式北斗导航定位系统信号接收机进行定位。北斗导航定位系统一般可用于( )