【单选题】A(An) is a document made out by the seller as a supplementary document to the commercial invoice to make up the deficiency of an invoice by giving all the necessaryparticulars of the goods.
【判断题】机械波的 波动 频率和波长与其波源的振动频率和波长相同。
【单选题】Major changes have been ____ in some developing countries in recent times.
【多选题】对柳永《望海潮》词中“羌管弄晴,菱歌泛夜”一句,分析正确的是 。