题干
—We just had a terrible accident.
—________But it's good to see you are all right.( )
A：Take it easy.
B：I'm sorry to hear that.
C：Don't be afraid.
D：It doesn't matter.
答案(点此获取答案解析）
B
合力对物块做功W和合力对物块作用的冲量大小为I，经历的时间为t，AB间的距离为s，则（ ）