G|--------9-7--------------------
D|------------9----9\4--5--4-----Play 2 Times
A|--7--7-------------------------
E|-------------------------------

G|--------9-7-----7-9-------------------
D|------------9-9--------4--5--4--------
A|--7--7--------------------------------
E|--------------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----
A|--7--7-------------------------
E|-------------------------------

G|-----------11-----10-----9---------
D|------------9------8-----7---------
A|--7--7-7--------------------10-----Play 8 Times
E|-----------------------------------

Bass chords? Yes. 
During the verses Tony Iommi is playing single notes during the descending chromatic 3 note run 
(B-A#-A) then hits a single G. Agreed? Good. Then where are the descending fifth chords coming from? Geezer is doing them.

G|--------9-7--------------------
D|------------9----9\4--5--4-----Play 2 Times
A|--7--7-------------------------
E|-------------------------------

G|--------9-7-----7-9-------------------
D|------------9-9--------4--5--4--------
A|--7--7--------------------------------
E|--------------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----
A|--7--7-------------------------
E|-------------------------------

G|-----------11-----10-----9---------
D|------------9------8-----7---------
A|--7--7-7--------------------10-----Play 8 Times
E|-----------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----Play 2 Times
A|--7--7-------------------------
E|-------------------------------

G|--------9-7-----7-9-------------------
D|------------9-9--------4--5--4--------
A|--7--7--------------------------------
E|--------------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----
A|--7--7-------------------------
E|-------------------------------

A|-7-7-7-7-7-7-7-7-7-7-7-7 Just Repeat The 7 Untill Guitar And Drums Stop

G|-----------------------------
D|------------5-5-5------------
A|--7--5--7-----------7-5------ Play 2 Times
E|-----------------------------

G|----------------7-9--------------------------
D|----------7--9---------------7--8--7---------
A|--7--10--------------7--10------------10----- Play 2 Times
E|---------------------------------------------

G|-----------------------------
D|------------5-5-5------------
A|--7--5--7-----------7-5------ Play 4 Times
E|-----------------------------

G|----------------7-9--------------------------
D|----------7--9---------------7--8--7---------
A|--7--10--------------7--10------------10----- Play 2 Times
E|---------------------------------------------

G|-------------------------------------------
D|-------------------------------------------
A|--7--6--5------------7--6--5--------------- Play 2 Times
E|-----------7--6-5-------------7--6-5-------

G|-------------------------
D|----------------5--------
A|--5--5--5--5h7-----7----- Play 2 Times
E|-------------------------

G|----------------------
D|----------------5-----
A|--5--5--5--5h7--------
E|----------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----Play 2 Times
A|--7--7-------------------------
E|-------------------------------

G|--------9-7-----7-9-------------------
D|------------9-9--------4--5--4--------
A|--7--7--------------------------------
E|--------------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----
A|--7--7-------------------------
E|-------------------------------

G|-----------11-----10-----9---------
D|------------9------8-----7---------
A|--7--7-7--------------------10-----Play 8 Times
E|-----------------------------------


G|--------9-7--------------------
D|------------9----9\4--5--4-----Play 2 Times
A|--7--7-------------------------
E|-------------------------------

G|--------9-7-----7-9-------------------
D|------------9-9--------4--5--4--------
A|--7--7--------------------------------
E|--------------------------------------

G|--------9-7--------------------
D|------------9----9\4--5--4-----
A|--7--7-------------------------
E|-------------------------------

G|-----------11-----10-----9---------
D|------------9------8-----7---------
A|--7--7-7--------------------10-----Play While It Fades Out
E|-----------------------------------