________ the question of how global warming has _________, we are doing some projects at school.
| A．Exploring, come about | B．To explore, come out |
| C．Having explored, come to | D．Being explored, come over |
The air has leaked out of this football.Could you get it ________ up?
| A．blow | B．blowing | C．blown | D．to blow |
________ the right decisions ________ the future is probably the most important things we'll ever do in our lives.
| A．Making；concerned | B．Made；concerning |
| C．To make；concerned | D．Making；concerning |
—What do you think made Celia so happy?
—________a prize in the recent competition.
| A．As she won | B．Won |
| C．Winning | D．Because of winning |
The wrong you have done to him is terrible，________， in my opinion，you should apologize to him.
| A．which | B．that |
| C．what | D．for which |
Those who have ________ floods and sandstorms know the importance of
environmental protection.
| A．gone over | B．gone through |
| C．got through | D．got over |