In fact, participants who took on the challenging intellectual tasks consumed up to 29.4 percent more calories than those who did not.

事实上，参与者在执行充满挑战的任务中消耗的热量比未参与者高29.4%。

youdao

if intellectual thinking were to deal only with the same problem, it would stop being intellectually challenging (see here).

如果智力思考只是用来处理同样的问题，它同样会失去智力思考的挑战性。

youdao

Labelling works as part of the global public domain is challenging as different countries have different intellectual property laws.

然而由于世界各国的知识产权法不尽相同，全球公有领域作品的标记工作充满挑战。

youdao

Gaining an understanding of and commitment to a new direction is a challenging intellectual and emotional task.

FORBES: Think You're Communicating Enough? Think Again

Success is 20% knowledge and 80% behavior, and one of the most challenging tasks of leadership is turning intellectual knowledge into habitual behavior.

FORBES: It's Not What We Think but How We Think: 3 Leadership Lessons from the IBM Executive School

He says securing intellectual property (IP) ownership has become increasingly challenging because of the volume of open-source knowledge and the huge number of existing patents.

BBC: Protecting that great idea with a patent