单选题

　　[填句补文]The Caribbean Islands form a chain that separates the Caribbean Sea from the rest of the Atlantic Ocean. ________. Many of the islands were formed by the eruption（爆发）of ancient volcanoes（火山）。Others are low-lying coral islands that gradually rose from the ocean.

　　A.They are famous for their warm， tropical climate and great natural beauty.

　　B.What would you see if you took a cruise to the Caribbean Islands？

　　C.They‘re like a long necklace that stretches between North and South America.

　　D.But life on the Caribbean Islands is not always paradise.