I have just started to learn the Japanese language this month and this is my first post on the forum. I was steadily reading through an online Japanese verb guide and I saw that in Lesson 47 (http://www.timwerx.net/language/jpverbs/lesson47.htm) it contrasts the verb suffix “sou desu,” which attaches to the dictionary “Base 3” form of a verb, with “sou,” which attaches to the “Base 2” form of a verb. However in the textbook that I’m using I saw the sentence, “Ame ga furisou desu,” in which it appears to me that “sou desu” is attached to the “Base 2” form of the verb. I hope one of the experts here will please inform me which one is correct. Does “sou desu” attach to the “Base 2” or the “Base 3” form of the verb?