阅读下面短文，按照要求用英语回答问题。（共5小题；每小题2分，满分l0分)
As we enjoy the summer ocean waves along the beaches，we may think nervously about Steven Spielberg’s Jaws and the great fear that sharks inspire in us．Yet we are happy to see global efforts to protect the declining number of sharks．The world has realized that we need the species，like sharks, to keep a balanced ecosystem．
Sharks，in particular，are“in’’these days．Thanks to good public policy and famous stars such as Jackie Chan and Ang Lee，killing sharks for fin soup is no longer cool．
The demand for shark fins has been rising for decades，threatening sharks with extinction(灭绝)-up to 100 million sharks are killed each year just for their fins．But we have started to reverse the trend，particularly in many areas of the United States and overseas where restaurants once proudly provided delicious shark fins on the menu．
In California，a ban on the sale and possession of shark fin soup has gone into effect this year through the efforts of Wild Aid and other organizations.
Overseas marketing and public efforts featuring posters on public transportation systems and TV ads have been underway for the past few years．These efforts all show signs of success, on both the supply side and the demand side of trade in shark fins．
Actually，stopping the killing of sharks is part of a broader movement to stop the killing of wild animals and the buying and selling of wildlife products．These products come from hunting elephants, tigers and rhinos，besides killing marine life．
Whether it is shark fin soup or ivory piano keys，killing animals is big business．The hunting of elephants in search of ivory tusks for luxury(奢侈的)goods has become a fall-scale war．The decrease of African elephant populations is alarming. Together with international partners, the United States is leading the worldwide effort to reduce demand for high-end products that rely on killing animals．
Why do people begin to make efforts to protect the declining number of sharks?
(No more than 15 words)
What’s the main reason for killing sharks?(No more than 10 Worals)
Who helped California decide to ban the sale and possession of shark fin soup?
(No more than 5 Words)
What does the underlined word‘‘reverse”in Paragraph 3 mean?(1 word)
In your opinion，what’s the best way to stop killing animals?(No more than 20 words)