mouth shape的用法和樣例：
例句
- Tamber is influenced by many factors such as mouth shape, tongue shape, breath, pose and harmonica itself.
口琴的音色受很多因素的影響，比如口形，舌頭的位置，呼吸方式，持琴姿勢，琴本身的音色特性，甚至錄音也會對其產生影響。 - One day in the class I could not pronounce a diphthong - not opening my mouth wide enough - since I was from the Northeast, no matter how many times Teacher Zhang corrected me.
有一次，張老師糾正我的發音，說我這個東北人，雙母音口形總是張不開，一再嬌正也發不好。
