daunting (adj.) intimidating, causing one to lose courage (He kept delaying the daunting act of asking for a promotion.)
cacophony (n.) tremendous noise, disharmonious sound (The elementary school orchestra created a cacophony at the recital.) cadence (n.) a rhythm, progression of sound (The pianist used the foot pedal to emphasize the cadence of the sonata.)
atom 原子(化学变化中的最小粒子) atomic mass 原子量 atomic number 原子序数 atomic radius 原子半径 atomic structure 原子结构