give up 与give in 都有“放弃，让步”之意，但give up 指行为者碰到某种困难或原因而自己主动放弃；give in指行为者屈于某种压力而被迫按别人的要求去做，侧重于屈服。give up可作vt., 后接名词或动名词作宾语；而give in只作vi. ,后不接宾语。如：
They decided to give up their plan. 他们决定放弃计划了。
What a heavy smoker you are! Give up smoking and take more care of yourself !你个烟鬼，把烟戒了，多关心一下自己吧！
His mother gave in and bought him a new bike. 他母亲拗不过他，只得给他买了一辆新自行车。