1、 意为“在……旁”，“靠近”。
Some are singing and dancing under a big tree.Some are drawing by the lake.
有的在大树下唱歌跳舞。有的在湖边画画儿。
2、意为“不迟于”，“到……时为止”。
Your son will be all right by supper time.
你的儿子在晚饭前会好的。
How many English songs had you learned by the end of last term？
到上个学期末你们已经学了多少首英语歌曲？
3、表示方法、手段，可译作“靠”、“用”、“凭借”、“通过”、“乘坐”等。
The monkey was hanging from the tree by his tail and laughing.
猴子用尾巴吊在树上哈哈大笑。
The boy’s father was so thankful that he taught Edison how to send messages by railway telegraph.
孩子的父亲是那么的感激，于是他教爱迪生怎样通过铁路电报来传达信息。
4、表示“逐个”，“逐批”的意思。
One by one they went past the table in the dark.他们一个一个得在黑暗中经过这张桌子。
5、表示“根据”，“按照”的意思。
What time is it by your watch？你的表几点了？
6、和take ， hold等动词连用，说明接触身体的某一部分。
I took him by the hand.我拉住了他的手。
7、用于被动句中，表示行为主体，常译作“被”、“由”等。
English is spoken by many people.英语被许多人说。（即“许多人讲英语。”）