题型:判断题 The loading, unloading, transshipment and transit of inward and outward mail bags are subject to Customs control and a ______ wya bill should be submitted to the Customs by the enterprise providing prviding postal service.A.coverB.coveringC.coveredD.haveing covered 查看答案
题型:判断题 在做“探究凸透镜成像规律”的实验时,发现烛焰的像在光屏的下边沿处.(1)不改变烛焰和屏的位置,只移动凸透镜,应将凸透镜向______(填“上”或“下”)移动,使像移动到光屏的中央.(2)不改变透镜和屏的位置,只移动烛焰,应将烛焰向______(填“上”或“下”)移动,使像移到光屏的中央. 查看答案