题目内容：

完成句子。根据所给汉语和句子意思，用英语补全句子。

1.—I think Maths is so difficult ，but it’s useful, isn’t it?

—Yes, you’d better                               (不要放弃学习它). It will help you much in the future.

2.Huang River is_______________________________(第二长河) in China.

3.When I saw a big dog , a moment of fear ___________________（我的脑中掠过一阵恐惧）.

4.You should take a rest _______________________________(在辛苦了一天的工作后).

5.—Did your Dad visit Lianyungang，a beautiful seaside city？

—Yes，he                                      (去那里出差两次).