他们又是跳绳，又是玩接球，等着上课铃声响起。They skip rope and play catch, waiting for the bell.跳绳是最有乐趣的有氧健身运动之一。Skipping is one of the most enjoyable aerobic activities.外面孩子们一边跳绳一边唱着歌。Outside, children were skipping and singing a rhyme....
Structural changes of dental enamel , dentine, cementum and pulpal reactions in carious process are discussed.其中,釉质龋的研究资料最为丰富, 其次是牙本质, 有关牙骨质龋的资料最少.Suitable for cutting metal , such as structural steel refractory steel, c...
He stowed away on a ferry and landed in North Shields.他偷乘渡船到了北希尔兹。Spears hurtled against shields.矛猛击在盾上.Radiation shields are commonly used to reduce radiation errors.辐射屏蔽罩一般用于降低辐射误差....