填空题 Tropical rain forests are found in the Amazon region of South America, as well as in Central America, Africa and Asia. Almost half of the rain forests are Brazil. Tropical rain forests are very old, thick forests where it rains more than 1.8 metres per year. The oldest rain forest in the world is in Sarawak. It is 10 million years old, and it has 2,500 different kinds of trees.
1 The lowest branches of the trees are about ten metres above the ground. Below the trees, there is another level of plants that consists of many kinds of smaller trees, shrubs, and flowers.
2 The lower level is protected by the trees above. The temperature and humidity (the amount of water, or moisture, in the air) stay about the same in the lower level. There is not much sunlight. In the upper level, the sun, rain, and wind change the temperature and humidity often.