machine head的用法和樣例：
例句
- There is a bolster across the head of the bed.
床頭上有一個長枕墊。 - The general was lying on the bed, his back against the headboard, hands clasped behind his head.
將軍躺在床上，背靠床頭板，頭枕在交疊的雙手上。 - Spindle feeds and speeds are controlled by selector levers which engage the proper gears in the drill head.
主軸的進能量和轉速是通過選速桿使主軸箱中的適當齒輪相嚙合而控制的。
