划掉与段落内容无关的句子
Read the following paragraph and cross out TWO irrelevant sentences.
    Rain forests, such as those in South America and Africa, contain more plant and animal species than does any other area in the world. For example, more bird species have been identified in a wildlife preserve in Peru than in the entire United States. The bird species will eventually die off if their habitat is not protected. At least 700 different tree species have been found in one forest in Borneo. That same number exists in the whole of North America. Amazingly, only 6-7% of the total land surface on Earth is covered by rain forests. One river in Brazil contains more species of fish than all the rivers and lakes in the United States together. If nothing is done to prevent these rain forests from being cleared, untold numbers of plant and animal species will certainly be endangered. And to protect these rain forests, the governments should take urgent and effective measures.