When students are not trained to think or work yourself. Thus dependent on others, such as students copying homework and do not be friends. Lead to the test not .
When students are not trained to think or work itself, so it must rely on other people, such as students ' homework may not be made until friends led to a complete examination is not .
When the students have not been trained to think or work itself, it must depend on other people, such as students who wrote the friend's house to make yourself, do not lead to an examination do not.