---Have you heard that Tom, as well as his parents, ________ moved to Beijing ? ---Really ? No _________ I haven’t seen him for a long time.

A number of students ______ playing on the ground but I don't know what the exact number______.

--Why does the lake smell terrible?    ---Because large quantities of water ______.

The population of China ________ 1.3 billion，and 80% of the population________farmers.

Either you or one of your students _______to attend the meeting that will be held tomorrow.