Mary had to go to a meeting，so she left her children ___________ at home.

Tom realized that he ________ his physics book at home when he reached school.

How many _______ teachers are there in your school –_______ them is over two hundred.

ly reports have_____ as often as several times a week, causing a wide concern and discount oftrust among the public.

He tried his best to solve the problem,_______difficult it was.