In persons over 35, periodontal disease causes the loss of more teeth than does dental caries, or decay . 在35岁以上的人中，牙周病引起的脱齿比龋齿还多。
The tab contains a toothed wheel which is driven at a high angular velocity by the impinging airstreams . 舵片上有一个带齿的轮，这个轮受到气流的冲击而高速转动。
The four main types of gears (spur, helical, worm, and bevel)and a rack and pinion are shown in figure 7 . 图7所示是四种主要的齿轮（巨齿轮，斜齿轮，蜗轮和伞齿轮）以及齿条和小齿轮。
At the incredulous tone, colorel's fleshy mouth widened in the grin which no doubt charmed the women . 听到这种怀疑不信的腔调，彼得斯上校厚实的嘴张大了，露齿而笑，它无疑很叫妇女们着迷。
Gregson surveyed the sea of curious faces, paused for effect, then permitted himself a broad grin . 对着一张张好奇的脸，格莱戈森扫了一眼，为了集中大家的注意力，他稍作停顿，然后露齿一笑。
The vegetation was mostly grass, with some ferns and bushes but few trees: there was little protection from the weather . 植物多为青草，另外还有一些羊齿蕨，灌木丛和为数不多的树木，统统处于狂风暴雨的无情折磨之下。
He jumped from the cart, and having told the groom to take the mare home, made his way towards his guest through the withered bracken and rough undergrowth . 他从车上跳下，关照车夫把母马牵回家，然后踩着枯萎的羊齿和蓬乱的灌木向客人走去。
Respecting the elders and loving the infants in zhou dynasty 周代的尊老尚齿制度
" the bamboo had a different purpose t han the fern "竹子和羊齿各有不同的作用。
The upper and lower jaws are broad with large teeth 上，下颌骨是广阔的大牙齿。
