You should notice that some of the verb forms look the same. You can say they have the same shape. For example, the plain present and the plain form of "walk" have the same shape. The same is true for the past and the past participle. But these different forms can have different shapes in other verbs. For example, the plain present of "be" is usually "are" but the plain form is "be". Also, the past of "eat" is "ate", but the past participle is "eaten". When you look for a verb in the dictionary, it is usually the plain form that you look for.