【判断题】By the mid-19th century, the territory of the United States had reached over 10 million square kilometers, about 9 times the size of the total area of the original thir states.
【单选题】Cargo ships can be divided into two basic types. One type carries dry cargo,the other carries liquid cargo; however,an OBO ship is designed to carry both. A traditional dry cargo ship is the multi-dec...