intact是指一样实体东西完整没被破坏
The plane was still intact when it landed. 飞机降落的时候没有损坏.
complete很简单, 就是通常的完成, 完整意思.
I've completed my homework.
If I can have you as my girl friend, my life will be complete. 如果你能当我女朋友, 我的人生就完整了.
integral 是指xxx中不可缺少的一部分
Playing games is an integral part of my life. 玩游戏是我生命中不可缺少的一部分.
whole整个, 完整
The whole world is watching you.