(Reading is useful) What kind are the subject and predicate in the previous sentence?

The answer is: Single.

Reading is helpful. The subject and the predicate in the previous sentence are both singular. Both refer to the idea that reading is useful and information shared in a sentence. Reading is an important activity that can help us gain knowledge and understanding. It can open our minds to new ideas and perspectives and can help us develop our critical thinking skills. Reading is also good for our overall well-being by reducing stress and helping us to relax. So, reading is very useful indeed, which is why both the subject and the news in the previous sentence are singular.