"Lower" can be used to describe the pitch of a sound, such as a person's voice or the sound made by a musical instrument. To describe the pitch of a sound as lower, you can say "The sound is lower in pitch."

For example:

"His voice is lower than hers." (他的声音比她的低。)
"She played the cello with a lower sound than usual." (她用比平常低的声音演奏大提琴。)

"Lower" can also be used to describe the position of something in relation to something else. For example, you can say "The books are lower on the shelf." (书在架子上的位置更低。)

"Lower" can also be used as a verb to mean "to cause to move to a lower position." For example:

"He lowered the flag to half-mast." (他把旗帜降到半旗。)
"She lowered the window to get some fresh air." (她把窗户打开来获得新鲜空气。)

The word "lower" comes from the Old Engpsh word "lēower," which means "lower in position, degree, or rank." It is related to the words "low" and "down."