The audience stood and （ ） at the end of the performance.

The Quality Control Staff is responsible _____ the quality of the products that come out of the factory.

The degree （ ） you maintain your mental health may depend on certain simple environmental factors.

Such problems （ ） air pollution and traffic jams are becoming more and more serious in some big cities.

（ ） the price, it is a thousand times worth it.

We decided to move to a quiet place, for we couldn’t （ ） the noisy environment here any more.

I got so tired that I just couldn’t move a step _____.

The tall tree, （ ） leaves are darker than those of the other two, is as old as grandpa.

Because they are （ ） a date, many of us believe that they are in love.

_____ the flood， the ship would have reached the destination on time.

He works too hard.That’s _____ is wrong with him.

—Do you know （ ） they got to know each other? —It was last year （ ）they both taught Chinese in Scotland.