[The Passive] The passive forms of the present and past progressive

The secretary is copying some letters.

Some letters are being copied by the secretary.

Someone is building a new hospital.

A new hospital is being built.

We couldn't use our classroom yesterday because someone was painting it.

We couldn't use our classroom yesterday because it was being painted.

Dogs usually wag their tails while people are petting them.

Dogs usually wag their tails while they are being petted.

Many of the older people in the neighborhood were growing vegetables to help with the war effort.

Vegetables were being grown by many of the older people in the neighborhood to help with the war effort.