The document provides sentences with different meanings and their corresponding explanations. Sentence 1 and 2 both refer to going to the gym but with different obligations, with sentence 1 being a want and sentence 2 being a requirement. Sentence 3 and 4 address note taking, with sentence 3 meaning it is unnecessary and sentence 4 prohibited. Sentence 5 and 6 cover obligations, with sentence 5 prohibiting talking and sentence 6 requiring wearing a hard hat on a construction site.