三年级英语书签上的名言名句可以包括以下这些：

No man is worth your tears, and the one who is, won't make you cry.

没有人值得你流泪，值得让你这么做的人不会让你哭泣。

To the world you may be one person, but to one person you may be the world.

对于世界而言，你是一个人；但是对于某个人，你是他的整个世界。

Live an noble and honest life. Reviving past memories in your old age will help you enjoy your life again.

过一种高尚而诚实的生活。当你年老时回想起过去，你就能再一次享受人生。

Just because someone doesn't love you the way you want them to, doesn't mean they don't love you with all they have.

爱你的人如果没有按你所希望的方式来爱你，那并不代表他们没有全心全意地爱你。

Life is but a span.

人生苦短。

Life is half spent before we know what it is.

人过半生，方知天命。

Life is not all roses.

人生并不是康庄大道。

Life without a friend is death.

没有朋友的人生是死亡。

Seeing is believing.

眼见为实。

Art is long, life is short.

人生短暂，学艺无穷。

Look before you leap.

三思而后行。

Like father, like son.

有其父，必有其子。

Better late than never.

再晚也不算迟。

这些名言名句不仅适合三年级学生阅读，还能激励他们在学习和生活中不断前进。建议将它们制作成书签，方便在阅读时随时参考和记忆。