Subject Phases and Clauses: Singular or Plural

[shauryagulati]

As per Manhattan SC Strategy guide,
Subject Phases and Clauses are Singular(Pg 42 4th Edition)

Can anyone tell me what about in the following que ( GMAT verbal review 2nd edition q-20):

Declining values for farm equipment and land,......., is going to force many lenders to....

It should be.. is or are.

Ans says: since values is plural it should be are,
but is't declining values a subject phrase??

[jnelson0612]

I'm sorry, but unfortunately by request of the GMAC we cannot use official GMAT questions on our forums or answer questions about them. Please see the forum guidelines here: read-before-you-post-mgmat-verbal-strategy-guides-t2719.html