______ is no need for primary students to work at their desks all the long.

Nowadays teenagers like to go to the fast food restaurant, ________, as the name says, eating needn’t take much time.

It is thought that one billion people in the world,_____ is half the world’s workers, earn their living by farming.

 It is almost five years_______ we saw each other last time.   

--Where did you see him for the first time?-- It was in the factory _________ we worked.