This is an example in G major. I am learning about Bach's chorales & how he uses modulation. I came across a page online (choraleguide.com), & in one example given, I couldn't understand what the author meant by the statement 4 on passing seventh.
The explanation given is: "at a cadence the passing note should be the seventh of the dominant chord - in this case C rather than E".
Also, I couldn't understand statement 5, which says: "the suspended D in the II7b chord needs to resolve downwards by step to C#".
I know that the chord II7b, V and I have consecutive 5ths between the Tenor & Bass parts. But I don't understand the point of the D resolving to C#. Is it because of the consecutive 5ths, or there is another reason?