.Most birds find it safe to sleep in the trees, but __________ they have eggs or young chicks, they don’t use a nest.
He talked about a hero _______ no one had ever heard.
The man _______ around our school is from America.
The doctor_______ is leaving for Africa next month.
The man _______ you are going to make friends is my father’s neighbour.
The man _______ you talked just now is a worker.