Cleft Object

[vjhutc]

I'm confused, whats a cleft object?

Also, whats the difference between object subject sentences and subject object sentences?

[Mister Micawber]

.
Cleft Object: It was the boy who the father dressed.
Cleft Subject: It was the boy who kicked the uncle.
Subject Object: The boy who the girl bit kicked the woman.
Subject Subject: The girl who hugged the father kicked the man.
.