It is uncertain ______ side effects these weight-loss drugs will bring about, although hundreds of thousands of patients have taken it.

The young man is ______ Edison in ourfactory and he has made ______ number of important inventions over the years

So why didn’t you meet us on Saturday then?—I’m sorry about that— I _________ — I thought you were meeting next Saturday.

Scientists have come to the conclusion_______ the temperature on Earth is getting higher and higher

How many students are there on theplayground —_________.