如图是关于人体免疫的卡通图解,根据图示回答下列问题:
我国位置最东的省级行政区是( )
如图,在等腰直角△ABO中,OA=OB=1,C为AB上靠近点A的四等分点,过C作AB的垂线l,P为垂线上任一点,则OP→·(OB→-OA→)等于( )
She was so busy ____(look) for her mobile phone that she didn't see a car coming.