candidate sets的用法和樣例：
例句
- Ordinarily, the candidate set for a call includes only member functions or nonmember functions but not both.
一般而言，函數調用的候選集只包括成員函數或非成員函數，不會兩者都包括。 - For a given query, we filter the whole graph through the index to get a smaller candidate set.Thus, high time-complexity subgraph isomorphism matching operations are reduced.
對於給定的查詢，我們使用這些索引過濾圖資料庫，得到較小的候選集，減少需要進行的高時間複雜度的子圖同構匹配。
