Problem: Generate a sentence that contains a fact.
Sentence: each of the moon 's phases usually occurs once per month

Problem: Generate a sentence that contains a fact.
Sentence: a pulley is used for lifting objects

Problem: Generate a sentence that contains a fact.
Sentence: if members of a species are born then the population of that species increases

Problem: Generate a sentence that contains a fact.
Sentence:
nature is the source of natural resources