Of course, they could not look at him with their eyes.

Please tell us the time by your watch.

All the work had to be done by hand.

通常所说，坐公共汽车、飞机、船去，英语用go by bus/plane/ship。实际上都不是指具体的交通工具，而是指通过某种交通的手段或方式。因此，by plane可说成by air，by ship可说成by water, by sea

with后的名词一般要用冠词，而by后一般不带冠词。

He writes a letter in ink. 他用墨水写信。

当行为动作和所使用的物品之间含有“在……中”意义时，也可用in

She held the book in her right hand.

He lay on his back. 他仰卧着。

to send voice over wires 用电线传送声音

有时over与on可互换

to listen to broadcast over/on the radio 用无线电收听广播

to cook over/on fire 用火煮东西

He built a telescope through which he could study the skies.

Scientists have found ways to make some useful things out of the waste materials and use them again. 科学家们已经找到了用废料提取有用东西加以重新利用的方法