换: 动词1.(给人东西同时从他那里取得别的东西) exchange; barter; trade 短语和例子用大米换布 exchange [barter] rice for cloth; 用鲜血换来的教训 a lesson paid for in blood; 那男孩用他的刀子换了一个板球棒。 the boy traded his knife for a cricket bat
齿轮: gear [rack; toothed] wheel; (toothed) gear; wheel gear 短语和例子伞齿轮 bevel gear; 斜齿轮 helical gear; 正齿轮 spur gear; 搭上齿轮 get [put; throw] into gear; 齿轮脱开 out of gear; 这个大齿轮带动小齿轮使滚筒旋转。 this large
