Train In Vain Bass

I have the main parts and the jist of the song here.  The only part I'm not sure about
the "You must explain" part.
 
Intro X4
G----------------------------------------------------------------------|
D----------------------------------------------------------------------|
A---6-7-7-7------------------------------------------------------------|
E----------4-7-7-7-----------------------------------------------------|
Verse 1, verse 2,
 
You said you loved me, and that’s a fact
G----------------------------------------------------------------------|
D----------------------------------------------------------------------|
A---6-7-7-7----6-4-4-4-------------------------------------------------|
E----------------------------------------------------------------------|
But then you left me, said you felt trapped
G-----------------------------------------------------------------|
D-----------------------------------------------------------------|
A---6-7-7-7-------------------------------------------------------|
E-------------4-7-7-7---------------------------------------------|
Well some things you can explain away
G-----------------------------------------------------------------------|
D-----------------------------------------------------------------------|
A---6-7-7-7---7-6-6-6---------------------------------------------------|
E-----------------------------------------------------------------------|
But the heartache’s with me til this day
G------------------------------------------------------------------|
D------------------------------------------------------------------|
A---6-5-4-4-4---6-7-7-7—---5-6-7-7---77----------------------------|
E------------------------------------------------------------------|
 
You must explain…      why this must be
G-----------------------------------------------------------------|
D---------- ------------------------------------------------------|
A-----------------4-------------------7-7-7-----------------------|
E-----------7--4---------------------------------4-7-7-7----------|
(repeat, Did you lie....)
X