Care is needed when loading the roll to prevent twisting or kinking the film...装胶卷时要小心，别使胶片扭结。Describes the static calibration methods of accelerometer: gravitational attraction method, loading method and centrifuge meth...
滑滑板时带护肘和护膝是必要的.Elbow pads and knee pads are essential on a skateboard.所有参赛者比赛时都必须佩带安全头盔及护膝、肘等可能必要的安全护具.It is mandatory that riders wear and approved safety helmet during racing.我要一副护腕和两副护膝.I want a pair of wrist protecto...