题目内容：

完成句子

1.As we know, Beijing is ________________________________( 中国第二大城市)

2.那个小男孩玩的很开心， 很多玩具在地上放着。

The little boy was playing happily, with a lot of toys _____________________________.

3.平均而言，我每周花30 元钱。

____________, I spend 30 yuan every week.

4.在他三岁前，他没有见过他的父亲。

_______the time he was three, he _____________________his father.

5.他们终于意识到了事态的严重性。

At last they _______________ the seriousness of the situation.