Fill in the blanks according to Text B. (每空填一个单词。一题多空，答案之间用逗号，隔开。)1) By the year 2020, it is estimated that there will be more _____ people than _____ people.2) In the past, people _____ married and _____ married. Divorce was very difficult, expensive and took a long time.3) Many couples, mostly in their twenties or thirties, live together without getting married. They are also called ______ couples.4) Many women in Britain prefer to concentrate _____ their jobs and put _____ having a baby until late thirties.