Using relative clauses often causes considerable concern for
non-native speakers of English ¡V so much so that they are often avoided
completely. But they exist for an important reason; in English you cannot
pre-modify important nouns very much ¡V that is, you cannot place complex
modifications before the noun. You have to put such modifications after
the noun ¡V and that is what relative clauses are for. In some languages, and
Chinese is one, you can pre-modify a noun in an extensive and complex way but
this is not possible in English as the following example shows:
Avoiding the use of relative clauses in your writing will
limit you to simple structures which are unlikely to be adequate to express
complex ideas and which will detract from the overall style of your writing.
However, when the relative noun is not the subject of the
relative clause, the pronoun is normally omitted. You can see that we is
the subject of the relative clause, so it¡¦s possible to omit the pronoun:
This is the fruit we call a lemon.
A clause with a deleted relative pronoun is known as a ¡¥contact¡¦ clause.
'That' is usually less formal than who, which, etc.
For more information on relative clauses, see Murphy, R. (1988). English
Grammar in Use. Cambridge: C.U.P. Look in Units 88 - 92. This book is
available in CILL on the Grammar Shelf at Intermediate level.