Analysis of test questions: "Mountains are all north and rivers are all south" can intuitively reflect the distribution characteristics of mountains and rivers in the terrain. The terrain is flat, the surface is rugged, there are few plains, and the snow-capped mountains are continuous, which is inconsistent with the description in the poem. There are many rivers in Indochina Peninsula, most of which originate from China. Affected by topography, it flows southward through Indochina Peninsula and into the ocean. "Mountains and rivers all flow northward and rivers all flow southward" embodies the characteristics of alternating and vertical distribution of mountains and rivers. Therefore, question A is the correct choice.
Comments: Most mountains and rivers in Indochina Peninsula extend from north to south, such as Kaishan, Irrawaddy River, salween, Chao Phraya River, Mekong River, Changshan Mountain and Red River. There are many mountains between the north and south rivers. According to the actual topographical features, the poem describes the geomorphological features of "I live at the head of the river, you live at the end of the river, and all the mountains are north and all the rivers are south". Taking famous poems as the starting point and describing images, students can easily grasp the topographical features of Southeast Asia.