--You just think of yourself! You kept me waiting for at least three hours．–I am sorry that you________think so.

 But for their common interests, they_____ cooperated so smoothly in the investigation of the case.

It has been announced that all the students ______ put on the masks before going to school in case they are infected with SARS virus.

I wrote a letter to John for his help during my high school years. without which I  the college entrance exam.

—What happened to the young trees we planted last week?—The trees ____ well, but I didn’t water them.