In order to reduce   air pollution, many people want  a total _____on the playing of firecrackers (鞭炮)in many cities during the Spring Festival.

 ______ the works of Leonardo da Vinci, the Louvre Museum has more than 6,000 other European paintings, ranging from the13th century to the 19th century.

I think you are at the end of your ________ this time and need to turn to Pro. Smith for advice.

It ______ to me that I might try this way to deal with this problem. 

feather