[Ⅰ] Researchers brought two groups of 11­year­old boys to a summer camp at Robbers Cave State Park in Oklahoma. The boys were strangers to one another and upon arrival at the camp, were randomly separated into two groups. The groups were kept apart for about a week. They swam, camped, and hiked. Each group chose a name for itself, and the boys printed their group’s name on their caps and T­shirts. Then the two groups met. A series of athletic competitions were set up between them. Soon, each group considered the other an enemy. Each group came to look down onthe other. The boys started food fights and stole various items from members of the other group. Thus, under competitive conditions, the boys quickly drew sharp group boundaries.

[Ⅱ] The researchers next stopped the athletic competi– tions and created several apparent emergencies [which / whose] solution required cooperationbetween the two groups. One such emergency involved a leak in the pipe supplying water to the camp. The researchers assigned the boys to teams [making / made] up of members of both groups. Their job was to look into the pipe and fix the leak. After [engaged / engaging] in several such cooperativeactivities, the boys started playing together without fighting. 일단 협력이 경쟁을 대체하고 그룹들이 서로를 얕잡아 보기를 중단하자, 그룹 경계가 형성되었던 것만큼 빠르게 사라져 갔다.