[ S ] a sound similar to a series of quickly repeated knocks（连续重复的）嗒嗒声，嘎嘎声；连续短促的碰撞声

[ C ] a toy that makes a noise like a series of knocks（玩具）拨浪鼓

[ C ] a wooden device that when turned round and round produces a noise like a series of knocks（转动时发出嗒嗒声的木制）响板

[ C ] the part of a rattlesnake's tail that produces a noise（响尾蛇尾部的）角质环

[ T ] to worry someone or make someone nervous烦扰；使慌乱；使紧张

[ I or T ] to (cause something to) make a noise like a series of knocks（使）发出尖厉的敲击声；（使）发出嘎嘎声