以中文為母語的兒童是否於主要名詞在後的中文關係子句表現上 有主賓不對稱的現象，一直以來廣受爭議與討論。根據過去的研究結 果，本研究假設年齡為影響因素，以語句模仿實驗測試三個年齡組（分 別為三歲、四歲、及五歲）的兒童。實驗結果顯示，五歲兒童組在主 語關係子句（subject-gap RCs )的表現較賓語關係子句（object-gap RCs ) 為佳，其他兩組兒童則無此顯著表現。此外，與三歲兒童組比較，四 歲兒童組的表現較少為片斷式語句，但四歲兒童組又較五歲兒童組容 易丟失關係子句之標記「的」；這些現象說明年齡在關係子句的表現上 具有關鍵性，且四歲是關係子句表現的過渡時期。綜合以上可知，當 兒童能穩定地模仿關係子句，通常在四歲之後，他們的關係子句表現 能展現明顯的主賓不對稱；另外，我們的研究結果建議在評估兒童的 關係子句表現時，應將與年齡相關的發展制約（developmental constraints)以及認知處理制約（processing constraints)納入考量。

The issue of whether there is subject-object asymmetry in Mandarin-speaking children’s performance of head-final relative clauses (RCs) has been controversial. Hypothesizing that age may play a role in contributing to the mixed results found in the past research on children’s performance of RCs, we tested three groups of children of different ages (3-year-olds, 4-year-olds, and 5-year-olds) with a sentence imitation experiment. Our results show that while the 3-year-olds and 4-year-olds exhibited inconsistent patterns, the 5-year-olds consistently performed subject-gap RCs better than object-gap RCs. In addition, compared with the 3-year-olds, the 4-year-olds produced fewer fragmental non-target responses, but when compared with the 5-year-olds, they made more errors of dropping the RC marker DE, suggesting that age is critical in children’s performance of RC and age four is the transitional period. Based on these findings, we suggest that when children are able to imitate RC sentences stably, usually above age four, their performance of RCs exhibit clear subject-object asymmetry. Our findings imply that both developmental constraints and processing constraints associated with age should be considered when evaluating children’s performance of RCs in experiments.