Abstract 1. Introduction 2. Two Approaches to Grammatical Description 3. Diagnostics Distinguishing between Gerundive and Participial Complements 3.1. Bresnan's (2001) Diagnostic Tests 3.2. Some Residual Problems 4. Additional Remarks on NP-ing and Vp-ing Complements 4.1. The Sequence 'V1 Np V2-ing' 4.2. The Sequence 'V1 V2-ing' Revisited 4.3. The Double-ing constraint Revisited 4.4. The Permissibility of the Perfect Auxiliary 5. Summary and Conclusion References