1. 端點   quadrangle   convex   vertex   quadrilateral   Hint Half-n-half Clue   2. 平行四邊形   oval   quadrilateral   prism   parallelogram   Half-n-half Clue   3. 四邊形   prism   straight line   quadrangle   hemisphere   Half-n-half Clue   4. 段   parallel lines   segment   quadrilateral   quadrangle   Half-n-half Clue   5. 平行的線   quadrilateral   hemisphere   perpendicular lines   parallel lines   Half-n-half Clue   6. 半球   pentagon   hemisphere   edge   rhombus   Half-n-half Clue   7. 七邊形   edge   convex   ray   heptagon   Half-n-half Clue