以下是一些常用的六年级下册英语谚语：

1. A friend in need is a friend indeed. 患难见真情。

2. Where there is a will, there is a way. 有志者，事竟成。

3. An apple a day keeps the doctor away. 日食一苹果，医生远离我。

4. Practice makes perfect. 熟能生巧。

5. It's never too old to learn. 活到老，学到老。

6. Early to bed, early to rise, makes a man healthy, wealthy, and wise. 早睡早起，使人健康、富裕又聪明。

7. All work and no play makes Jack a dull boy. 只工作不玩耍，聪明孩子也变傻。8. Rome was not built in a day. 伟业非一日之功。9. A picture is worth a thousand words. 一图胜千言。10. Beauty is in the eye of the beholder. 情人眼里出西施。这些谚语可用于各种场合，帮助学生更好地理解和运用英语。可以鼓励孩子们多读、多背、多运用这些谚语，提高英语水平。