Think of the Japanese quotation particle と. Sou desu in Lesson 47 is like saying "...to iu hanashi desu" (the story that...). You cannot have polite verbs inside a quotation.
Keep practicing, and don’t hesitate to review Lessons 26 (Appearance) and 47 (Hearsay) side-by-side until the difference becomes second nature.
To master Lesson 47, simply memorizing the answers isn't enough. You need to understand the conjugation rules. minna no nihongo lesson 47 renshuu b answers
Appearance uses the verb stem (雨が降りそうです - It looks like it will rain), while hearsay uses the plain form (雨が降るそうです - I heard it will rain). 3. Conjecture based on Sights/Sounds (~ようです) Used when you have some evidence for your guess.
このレストランの料理はとても美味しい。 Kono resutoran no ryouri wa totemo oishii sou desu. Think of the Japanese quotation particle と
Note: These answers are based on the standard Minna no Nihongo II textbook curriculum. Section 1: Hearsay (~そうです)
外は暗いので、もう夜の ようです 。 (Since it's dark outside, it seems it's already night.) Keep practicing, and don’t hesitate to review Lessons
咳をしているので、風邪をひいた ようです 。 (Since they are coughing, it seems they caught a cold.) Section 3: Sensory Perceptions (~がします)
明日は雨です。(Ashita wa ame desu – Tomorrow will be rain.)