a three point lead的用法和样例：
- The fourth section starts, Robinson comes up hits two three-pointers, 92-80 Nix is in the lead, House retaliates a three point 84-92 Celts to continue to fall behind.
- S. public opinion at the American Enterprise Institute in Washington."In Gallup's national daily tracking [poll] for June and July, Obama has averaged a three percentage point lead over John McCain.
- Play continues until a two point lead is achieved.
- A three critical point theorem is proved.