单选题 In order to prevent stress from being set up in the metal, expansion joints are fitted which ______ the stress by allowing the pipe to expand or contract freely.
【正确答案】 A
【答案解析】[解析] relieve减轻，解除，援救。reconcile使和解，调停。reclaim矫正，感化，收回。rectify矫正，调整，纠正。