She is (a)   a sheep.

They are (a)   playing the banjo.

I'm (a)   going to the party.

We (a)   not very happy today.

John and Sue (a)   not brother and sister.

Alex (a)   not very tidy.

We are (a)   aliens from Mars.

He (a)   not angry with you.

The book ... not on the table.

(a)