Gratitude: standard: 1. Stick the palm of your right hand on your left chest. 2. The thumb and little finger of the left hand are extended; The thumb and forefinger of the right hand stretch out and stick to the chest, then move to the left hand to show sincerity to others.

Sign language (C) is a sign language for hearing-impaired people (deaf people, hereinafter referred to as hearing-impaired people) to communicate and exchange ideas with each other. It is an important auxiliary tool for oral English and the main communication tool for hearing-impaired people.