  Linguistic theories formulated in the architecture of {\sc hpsg} can be very
precise and explicit since {\sc hpsg} provides a formally well-defined setup.
However, when querying a faithful implementation of such an explicit theory,
the large data structures specified can make it hard to see the relevant
aspects of the reply given by the system. Furthermore, the system spends much
time applying constraints which can never fail just to be able to enumerate
specific answers. In this paper we want to describe lazy evaluation as the
result of an off-line compilation technique. This method of evaluation can be
used to answer queries to an {\sc hpsg} system so that only the relevant
aspects are checked and output.
