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....
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....