The changing of the diameterofpart a in mechanical products due to the influences of environment and age, and it would finally result in the uselessness of part a.
某机械产品中a零件受年龄及环境因素影响，直径发生变化，最终无法继续使用。
2
The height is 330 m, diameterof the lower part – more than 30 m.
烟囱高度达330米，底部的直径大于30米。
3
This image shows partof a 7.4-mile-diameter impact crater on Mars' southern hemisphere.