1. 垂線　   convex   edge   perpendicular lines   hemisphere   Hint Half-n-half Clue   2. 頭頂　   hexagon   oval   vertex   heptagon   Half-n-half Clue   3. 六角形   parallelogram   hexagon   convex   pentagon   Half-n-half Clue   4. 五角形   ray   pentagon   straight line   parallel lines   Half-n-half Clue   5. 凸面   hemisphere   ellipse   convex   plane   Half-n-half Clue   6. 四角形   pentagon   quadrangle   polygon   ellipse   Half-n-half Clue   7. 卵形   hemisphere   oval   quadrangle   polygon   Half-n-half Clue