Joe is not good at sports, but when it ______ mathematics, he is the best in the class.
—Derrick, don,t you think you should take a vacation? Even one or two days would be fine. —There's __________. There's too much work.
Cats and tigers are animals of the cat family (猫科动物), so cats __________ tigers in many ways.
The visitors you referred to __________ looking forward to __________ around our school.
Was it in 1969 __________ the American astronaut succeeded __________ landing on the moon?
I used to love that film __________ I was a child, but I don't feel it that way any more.