Her most annoying habit was eating with her mouthopen.
她最让人讨厌的习惯就是张着嘴吃东西。
《牛津词典》
2
"If you sleep with your mouthopen, she will be able to see the tooth hole," said Sammy. The class laughed. Come on! But that just gave me a great idea! "How did you get the Tooth Fairy to leave the money?"