（1）The Europeans had sour oranges earlier than sweet ones.
（2）From the eleventh century，sour oranges were widely grown all over Europe.
（3）Some businessmen first brought sweet oranges from Europe to the East.
（4）In the fifteenth century，sweet oranges were expensive and rare.
（5）It wasn't possible for the sweet orange trees to grow well in cold countries.
（6）Today，American produces more oranges than any other country in the world.