单项选择题 疼痛强度的评估工具有哪些（）

问答题 查阅资料，我国现有的大气环境污染物监测指标有哪些？其含义分别是？

未知题型 The causal relation encoded in the paragraph in Task 2.2 (Page. 51) is not a cause and effect in the conventional sense, but more of a logical deduction. Read the paragraph. Decide whether the following statements are true or false. 1. Sentence 1 is the topic sentence.