This thesis analyses the phenomenon of predicate-complement structure that is specific to "Verb (monosyllabic)+Adjective (monosyllabic)+了".This kind of predicate-complement structure is not symmetric, but the previous studies do not point out the reason s of such symmetry phenomenon. The adjectives which are researched in this article are limited to the 120 monosyllable adjectives in The Outline of HSK. According to the analysis results, there are 112 adjectives that can be used as the result complement, and 8 adjectives that can not be used as the complement; 63 adjectives that can act as the complement of the predicate-complement structure which can carry with the object, and 49 adjectives that can not act as the complement of the predicate-complement structure which can carry with object. By breaking down the predicate - complement structure, we can make the conclusion that the predicate-complement structure with object is constrained by the transitivity of verb, the semantic orientation of complement and the thematic role. 1) The transitivity of Verb: Relatively speaking, the predicate-complement structure formed by the verb with semantic dispose can carry with the object, otherwise it can not carry with the object. 2） The Semantic Orientation of Complement: When the semantic orientation points to the object or the predicate, the predicate-complement structure can carry with the object. When the semantic orientation points to the subject, the predicate-complement structure , except the idiomatic one, can not carry with the object. When the orientation is an object, the object can be the upper category noun or the subordinate category noun, while the object must be the upper category noun if the semantic orientation is a subject or predicate. 3) Semantic Role: According to the generative grammar, the nominal element related to the verb can act as a thematic role and only can include one thematic role. The theme can act as a subject or an object, but the experiencer can only be the subject of the verb and can not act as the object. Besides, the thematic element in its structure must have a relative position., as the "salty" in "food is salty" and "crooked" in "the box is crooked" in the second example, they express an unsatisfied result, which is caused by someone or some conditions - it`s someone or some conditions that cause the food become salty and the box become crooked. Therefore, instead of the theme, the "food" and "box" are the experiencer and must transfer the position from object to subject. These sentences belong to the implicit causative construction, and if they are the real words instead of the zero forms, they can each be changed into "He makes the food salty" or "He makes the box crooked".