教学目标
By the end of this section, students will be able to:
1. understand the meaning of restrictive relative clauses with relative pronouns;
2. summarize the grammatical rules of the restrictive clauses with relative pronouns;
3. apply 
the appropriate restrictive relative clauses with relative pronouns to describe their friends.
教学重难点
1. To understand the functions of different relative pronouns in the restrictive relative clauses;
2. To know the restrictions of different relative pronouns.
