A strange sentence

Today my English teacher taught us a strange sentence to help us remember the knowledge point"The man lying on the ground lied that a coke  cock laid an egg"

I think your teacher wants to show you different meanings of the verb 'to lie'.

'Lying' ..... to be stretched out on the ground.

'Lied' ........ told a falsehood.

'Laid' .......  to produce an egg (but of course a cock cannot do this because it is male!)

Hope this helps