The offer was so good that I didn't think twice before signing the contract.

didn't 是 do not 的缩写形式，表示否定。 think 的意思是"思考、考虑"。 twice 由词根 twi-（表示"二"）和后缀 -ce 组成，意思是"两次"。 didn't think twice 字面意思是"没有考虑两次"，引申为"毫不犹豫"。