--- Have you finished the report? --- No. I ______ it all this week.
It is the test system, _____ the teachers, that is to blame for the heavy burden of middle school students nowadays.
The manager meant ____ the workers that being 5 minutes late meant ____ the company.
Great changes ______ in China in the past 20 years.
The question is ______ it is worth doing.
The students were ____ over the ____ problem, listening to the teacher with a ____ expression on their faces.