I. Grammar 1. Insert prepositions in the slots.
It is a well-known rule ( ) logic that classifications made ( ) the basis of a single attribute are artificial and ( ) limited use. So there must be a cluster of attributes ( ) which a human group is defined, and these must be specific and essential, if they are to serve a useful purpose. Yet what is essential ( ) one observer is not ( ) another. Some would opt ( ) language, others ( ) race, religion, or shared destiny in the past or the present. It is also quite common to find that individuals tend to identify their own community ( ) criteria which may be different from those used ( ) the same purpose by outsiders. 2.Supply an article in the slot when necessary.
All ( ) books are divisible into two kinds; ( ) books of ( ) hour, and ( ) books of all ( ) time. Mark this distinction —it is not one of ( ) quality only. It is not merely ( ) bad book that does not last, and ( ) good one that does. It is ( ) distinction of ( ) species.