The book that Al had read was good

[ _ was good] (the book that Al had read)

G(Ix x is a book that Al had read)

G(Ix (x is a book ∧ Al had read x))

G(Ix (Bx ∧ Rax))

The book, which Al had read, was good

the book was good ∧ Al had read the book

G(the book) ∧ Ra(the book)

G(Ix x is a book) ∧ Ra(Ix x is a book)

G(Ix Bx) ∧ Ra(Ix Bx)

B: [ _ is a book]; G: [ _ was good]; R: [ _ had read _ ]; a: Al