dynamics：动力学，力学；(音乐中的)力度变化，力度强弱法 

词根词缀： -dynam-力 + -ics名词词尾,...学

• unrelenting
• unrequited
• unrest
• unscathed
• unscramble
• unsolicited
• unsophisticated
• unsound
• unsporting
• unstable
• unstinting
• unsuitable
• unsympathetic
• until
• unto
• untold
• untouchable
• unveil
• unwilling
• unwind
• unwonted
• unworldly
• up
• upbeat
• upbraid