当他因比赛发挥失常而想要自暴自弃时，朋友劝他以积极的态度来应对，而不是选择逃避。(feel)

When he felt like giving up (on himself) due to his poor performance in the competition, his friend advised him to face the situation with a positive attitude instead of choosing to escape.

考查短语和状语从句。表示 “当……时候” 用when引导时间状语从句，主语为he，表示 “想要做某事” 可用feel like doing sth.；表示 “自暴自弃” 可用give up (on oneself)；表示 “因比赛发挥失常” 可用due to his poor performance in the competition；主句主语为his friend；表示 “建议某人做某事” 短语为advise sb. to do sth.；表示 “以积极的态度来应对” 可用face the situation with a positive attitude；表示 “而不是” 用instead of；表示 “选择逃避” 用动名词短语choosing to escape。发生在过去用一般过去时。故翻译为：“When he felt like giving up (on himself) due to his poor performance in the competition, his friend advised him to face the situation with a positive attitude instead of choosing to escape.”。