It has been widely reported that many people, including gifted students and highly intelligent adults, may not be able to correctly identify statements of FACT as distinct from statements of OPINION.

This has given rise to a number of articles and exercises discussing the differences.

A few examples of web resources (some may be better than others):
1. Dictionary -

2. K5Learning -

3. SuperTeacherWorksheets

4. Miami Dade College, college prep -

Can your children distinguish between FACTS (truth) and OPINIONS (beliefs, feelings, viewpoints, perspectives)? Parents can guide their children in learning this important skill, whether using resources found on the web or by discussing events from their daily life, memorable encounters and lived experiences, books they are reading or have read in the past, current events, news stories, and more.

Related -
Oxford's Word Of The Year for 2016 was "post-truth," defined as:
relating to circumstances in which people respond more to feelings and beliefs than to facts.
Link to post - zeitgeist, encapsulated in Word Of The Year