Here is a longish paragraph.  During the execution of a program, it is
possible for an operation to be performed that is either illegal or
that leaves the program in an undefined state.  This sort of operation
is usually not intended by the programmer, and should therefore be
brought to his attention.  For this reason, a typical Oberon-2
run-time system provides mechanisms to detect illegal or undefined
operations and report them to the user.

Followed by another paragraph.  For OOC, an invalid operation is
signaled by the facilities defined in module `Exception' (*note
Exception Handling::.).  If detected, such an operation will raise an
exception of source `Exception.runtime' with an exception number from
the list defined in `Exception'.  If the raised exception is not
handled by the program, it will cause the run-time system to emit an
appropriate error message and terminate the program.

And a very short paragraph.
