Well, you know, it's difficult to explain.

唉，你知道，这很难解释。

《牛津词典》

It was difficult to explain the problem to beginners.

对初学者解释这个问题很难。

《牛津词典》

Although some sightings of UFOs are difficult to explain, most can be explained quite easily.

虽然有些目击 UFO 的现象很难解释，但大多数都可以很容易地解释。

youdao

She began to explain to the students how to solve a very difficult problem.

VOA: special.2009.10.25

And this is no surprise if what we are is the workings of our physical brains, but it is extremely difficult to explain if one is a dualist.

如果我们的本质就是生理大脑的活动,那这也就没什么可惊奇的,但对于二元论者来说,解释这些却是非常困难的

耶鲁公开课 - 心理学导论课程节选

But scientific information can be difficult to understand and even more difficult to explain to others.

UNESCO: Science Communication

That makes it all the more difficult to explain the specific dynamics of the latest moves.

FORBES: Violent And Panicky Gold Selling Collapse Bullion And Commodity Markets

Perhaps a little more difficult to explain are the undisclosed lobbying efforts uncovered by Playoff PAC.

FORBES: Playoff PAC Files IRS Complaint Against BCS Bowls