单选题 She worked hard at her task before she felt sure that the results would ______ her long effort.

【正确答案】 A

【答案解析】[解析] A项justify意为“证明……是值得的”，符合题意。B项testify意为“作证”； C项rectify意为“纠正，校正”；D项verify意为“证实”。