10.50Analyze that progression

In C:

Cmaj7 = I

A7 is not diatonic.

But A7 → Dm7.

So A7 is:

V7/ii

Then:

Dm7 = ii

G7 = V

So:

Cmaj7 → A7 → Dm7 → G7

is:

I → V7/ii → ii → V7

and likely returns to I.

You can already see how seventh chords create longer chains of harmonic gravity.