Is there anyone who can give me some ambigurous sentences in English?

I think what you are talking about is called "PUN",not "ambiguous".
Oh BTW,it's "ambiguous"
And~Here you go:
有一次老师问学生:Which runs faster,heat or cold?有的同学认为heat跑得快,有的则说冬天的冷空气来得迅猛,各持己见,难分难解.后来,老师笑着说:Heat runs faster,because you can easily catch cold.“冷”是一种气流,怎么能抓得住呢?直到老师把句子写到黑板上后,同学们才恍然大悟.原来catch cold是“感冒”的意思.人们常会catch cold,而从未听说过有人catch heat.既然“抓不住heat”,不言而喻heat比cold跑得快了.同音异意或一词多义的诙谐的词或句子,就是“双关谜语”pun.
大部分puns是文字游戏,其中有同音同形而异意的puns,例如：
——What trees has fire no effect upon?
——Ashes,when burnt,they are still ashes.
Ash在英语里既是“木岑树”,又是“灰烬”,不管怎么烧,ash（木岑树）仍然是ash（灰）.
——Why many carpenters reasonably believe there is no such thing as stone?
——Because they never saw one.
saw是see的过去时,又可作“锯”解,木匠当然不会去锯石头.
——What flower does everyone have?
——Tulips.
tulips['tju:lips],郁金香,发音相当于人的“两瓣嘴唇”two lips.
——What trees come in two's?
——Pear trees.
pear梨子,发音同“一对”的pair相同.
还有一些用“成语”（idioms）构成的puns,例如：
——Why is a dog biting his tail like a good manager?
——Because he makes both ends meet.
make both ends meet是狗咬尾巴时首尾相触的动作,而这一短语又可作“收支平衡”的成语,能做到收支平衡当然是个好管家.
——Why is crow the bravest bird in the world?
——Because it never shows the white feather.
crow乌鸦没有白羽毛,但是show the white feather又是一个意为“胆怯”的成语.
英语的puns很多,不全是文字游戏,有的是很辛辣的讽刺.例如：
——Why is a restless man in bed like a lawyer?
——Because he lies on one side then turns around and lies on the other.
有心事的人总是躺在床上翻来覆去睡不着,可是lie又可作“撒谎”.