18.四个球队比赛,任意两个球队都要赛一次,共要组织( )场比赛.
0 159716 159724 159730 159734 159740 159742 159746 159752 159754 159760 159766 159770 159772 159776 159782 159784 159790 159794 159796 159800 159802 159806 159808 159810 159811 159812 159814 159815 159816 159818 159820 159824 159826 159830 159832 159836 159842 159844 159850 159854 159856 159860 159866 159872 159874 159880 159884 159886 159892 159896 159902 159910 199269
| A. | 8 | B. | 7 | C. | 6 |