If you show understanding, you show that you realize how someone feels or why they did something, and are not hostile toward them.
理解; 谅解
If you are understanding toward someone, you are kind and forgiving.
能理解的; 体谅的Her boss, who was very understanding, gave her time off. 她的老板很体谅她,给她放了假
They have to have a basic understanding of computers in order to use the advanced technology.
为了利用这一先进技术他们必须对计算机有基本的了解。