The sun was falling behind the hills.

太阳在山丘后落下。

The fear of falling behind in efficiency.

担心在效率上落后。

Although Europe's economy was growing, it was falling behind relatively.

尽管欧洲经济也在增长，但相对而言还是落后了。

Am I really falling behind?

那么，我确实落后了吗？

They'll end up to be falling behind others,

最终只能落在别人的后头，

Thereupon, it finds a treetop falling behind.

于是，它找到一枝树梢落下。

To slacken the tempo would mean falling behind.

放松步伐就意味着落后.

No modernization means poverty and falling behind.

没有现代化、就意味着贫穷与落后。

He's been falling behind his group members in English.

他在英语方面一直落后于同组同学。

The work of this class has been falling behind recently.

最近这个班的作业质量一直在下降。