作物【zuò wù】
crop
[名]农作物的简称

大米和小麦是中国主要的农作物。
Rice and wheat are the main crops of China.
作业【zuò yè】
1. school assignment; homework; task 2. work; task; operation; production
[名]1、教师布置的功课 2、为完成生产和军事训练任务等而布置的活动

我希望同学们认真完成作业。
I hope that every student will do his homework seriously and carefully.

整个作业的安全让一个粗心大意的人给破坏了。
The security of the whole operation has been jeopardized by one careless person.
作用【zuò yòng】
1. action; effect; function; influence 2. act on; affect; influence
[名]1、对人或事物产生的影响或功能、效果 [动]2、对事物产生影响

舆论的作用是不可忽视的。
The function of public opinion cannot be ignored.

一切事物都是互相联系并且相互作用的。
All things are interrelated and interacted.