One issue that has been discussed rather widely in the literature of Mandarin Chinese control structures is whether the complement clauses are finite or non-finite clauses. This question has received much attention partly because Mandarin Chinese is a language with few morphological markings. There is no indication of grammatical tense on the verb; there are also no overt complementizers. Thus there is no obvious way to distinguish a finite clause from a non-finite clause. This makes it a challenge to distinguish between different types of clauses. In this study I will re-examine control complements in Chinese. However, I will not take a position as to whether they are finite or non-finite; rather, I will show that control complements are not uniform in structure. In particular, certain control complements show clause union (restructuring) effects. I will present evidence to show that control complements are of two types. I will offer an account of the differences between the two types of complements in terms of temporal properties. I will also review some arguments that have been used in the finite vs. non-finite debate and show how they reveal the non-uniform nature of control complements. The existence of clause union in Chinese control complements has implications for other areas of grammar. I will explore some of these in the talk.