A:F甲=F乙,ρ甲=ρ乙
B:F甲=F乙,ρ甲<ρ乙
C:F甲<F乙,ρ甲=ρ乙
D:F甲>F乙,ρ甲>ρ乙
物体沿一条直线运动,下列说法正确的是( )
_________ he was very tired, he continued working in his office.
我们在生活中会受到诸如“严禁考试作弊”“公共场所严禁吸烟”等规定的限制。这是因为