这个问题千头万绪，三言两语说不清楚。

This problem is too complicated to be explained in a few words.

《新英汉大辞典》

当然，说着容易做着难。要想放下千思万绪而专注于目前必须做的或是想做的是很难的。

Of course, it's much easier said than done to empty your mind of everything and focus on what you have to or want to do at the moment.

youdao

保护和补助”不成熟产业”直到该产业有足够实力在海外竞争，这样的主张是千头万绪的。

The argument for protecting or subsidising “infant industries” until they have become strong enough to compete abroad is complicated.

youdao