The intro starts out in G. You have to capo 1.
G
Keep a knockin' but you can't come in keep a knockin' but you can't come in 
D                                      G
keep a knockin' but you can't come in come back tomorrow night and try it 
        G
again. You said you love me but you can't come in you said you love me but 
                   D                                           G
you can't come in you said you love me but you can't come in come back 
                                   G,D   G
tomorrow night and try it again. (Solo) Keep a knockin' but you can't come 
                                        D
in keep a knockin but you can't come in keep a knockin but you can't 
        G                                           G
come in come back tomorrow night and try it again. You said you love me 
                                                                  D
but you can't come in you said you love me but you can't come in you said 
                                   G
you love me but you can't come in come back tomorrow night and try it 
        G,D    G
again. (Solo) Keep a knockin' but you can't come in keep a knockin' 
                       D                                     G
but you can't come in keep a knockin' but you can't come in come back 
                                  G
tomorrow night and try it again. You said you love me but you can't 
                                                    D
come in you said you love me but you can't come in you said you love me 
                       G
but you can't come in come back tomorrow night and try it again.

(Fade to end in G)