China's present environment situation is from bad to worse and if we _________ now to protect the environment, we’ll live to regret it. 

Ladies and gentlemen, please fasten your seat belt. The plane __________. 

（2014年(春)重庆市高三考前冲刺测试卷）8.  Asia ______ the popularity of South Korean culture that has been flooding other countries since turn of the century.

—— Did you hand in your application for a league member?——Not yet. If I _____to see my father, I would have.

—You may find the key to the math problem on page 107．—Ah, it's so simple. I wonder why I _____ of that．