They had dug the pond=The pond had been dug by them.

They elected me secretary. (Passive) = I was elected secretary by them.

They elected him captain.   = He was elected captain by them.

They came home while I was studying.

There was dust on the floor.

There lived a certain king. 

There is two High School is our village. 

= There are two High School in our village.

There is none to look after her. 

There is no rose but has a thorn. (Affirmative) = Every rose has a thorn

There is no mystery greater than misery

There is no mother but loves her child.

There is no doubt about his honesty.

There is a bank right on the street.

The water in the pond is dirty.

The train is very tall = How tall the train is !