本文研究了一种新型行星传动 —— 滚锥齿超环面行星蜗杆传动.The paper researches a new type mechanical transmission mechanism - the Rolling cone - type toroidal drive.'环'.''面,环形圆纹曲面圆圈形成的超''.'环'.''面; 具...
It is only the sensational that sells news magazines.只有轰动性的事件才能促进新闻杂志的销售。The company buys and sells about 600,000 barrels of oil a day.该公司每天买卖约60万桶石油。The co-op sells the art work at exhibitions.这家合作社在展览会上销售艺术品。...