____________ is playing with ____________ ball.[ ]
A. he; his
B. She; his
C. He; his
答案:C
图书馆的类型,按用户群划分有综合性图书馆和专业性图书馆。
汽车以10m/s的速度匀速行驶,遇情况急刹车作匀减速运动,加速度大小为2m/s²,则经过3s后的速度大小是()m/s,经过6s后的速度大小是()m/s。