—Mr. Smith, why are you always asking me to do the difficult work?—Because you _______ do such a thing and nobody else is fit for it.

Finally, the team reached the top of the mountain,       they found some rare plants.

I chose the most popular major instead of my favorite one，but I had to drop out and started again where I＿＿＿have gone in the first place.

You _______ cross the road when the traffic lights are red.

【There’s a lot of water on the ground; the water pipe _____ be repaired.