---Humans are slowly polluting the whole world and there is not enough clean air _____ water.

---Humans are slowly polluting the whole world and there is not enough clean air _____ water.

---I agree. We must take action, _____ things will be worse.

A. and; and B. or; and C. and; or D. or; or

【答案】

D

【解析】

句意：人类正在慢慢污染整个世界，没有足够的清洁空气或水。我们必须采取行动，否则情况会更糟。考查连词辨析题。and和or都是连词。and和，表并列；or或者，表选择；并列结构中，or通常用于否定句，and用于肯定句。or还用于连接两个并列的句子，意思是“否则”。there is not enough clean air or water.是否定句，根据句意，故选D。