Abstract 1. Introduction 2. Negative Polarity 2.1. Negative Polarity Use and Free Choice Use 2.2. C-Command Condition 2.3. Checking Approach 3. Complementizers and Complements 4. Complementizer Transparency 4.1. Raising-to-Object and the Modification of Adverbial Clause 4.2. Complementizer Transparency and NPI 4.3. No C-Command Requirement for Licensing an NPI 5. Conclusion References