答案：During the holiday，many students apply for the overseas exchange program to improve their oral English，expand their horizons and know about the local cultures，which will have a positive effect on their future learning and work．
句子里apply for 表示"申请"；expand their horizons 表示"开拓视野"；which引导非限制性定语从句，代指主句；have a positive effect on 表示"对…有积极影响"． 答案：During the holiday，many students apply for the overseas exchange program to improve their oral English，expand their horizons and know about the local cultures，which will have a positive effect on their future learning and work．
句子里apply for 表示"申请"；expand their horizons 表示"开拓视野"；which引导非限制性定语从句，代指主句；have a positive effect on 表示"对…有积极影响"．