The sound is virtually undetectable to the human ear.
这声音实际上是人耳难以听得到的。
She leaned over and whispered something in his ear.
她探过身去附耳跟他说了些什么。
The dog scratched itself behind the ear.
狗用爪子挠挠耳后。
She whispered something in his ear.
她对他耳语了几句。
Hard hats and ear protectors are provided.
提供安全帽和护耳。