The waywardness and sound quality of domestic whistles can't be compared with Wan Delin, and Feiyan is even worse. The material of the domestic whistle that Ruili can still take is soft. Your children are not used to wandering. Let him practice his long voice more, and he will soon find that his voice will get better. Specifically, let the teacher see whether it is objective or subjective. If it's really hard for him, he needs to be on sentry duty. QQ 103700277