1. 线   line   circle   semicircle   perimeter   Hint Half-n-half Clue   2. 半圆   cone   triangle   semicircle   circumference   Half-n-half Clue   3. 周长   triangle   angle   square   perimeter   Half-n-half Clue   4. 点   volume   point   circumference   circle   Half-n-half Clue   5. 半径   volume   cube   radius   triangle   Half-n-half Clue   6. 圆周   sphere   diameter   curve   circumference   Half-n-half Clue   7. 长方形   volume   rectangle   line   angle   Half-n-half Clue