Adjective Clause
Adjective clause is a clause that functions as a adjective. As we have seen, adjectives are words that describe nouns. Thus, it also serves as an adjective clause, which gives details on the noun.
Adjective clauses beginning with relative pronoun or relative adverb.

1. Adjective clause with relative pronoun
   Example:
   The Man Who is sitting over there is my father.
   The book the which you bought yesterday is very interesting.
   This is the place that i visited some years ago.
   Mr. Tarno Whose son is my friend is presenting a paper in a seminar.
   
2. Adjective adverb clause with a relative
   Example:
   This is the reason why she did it.
   The time when the plane takes off and lands will be changed soon.
   Pematangsiantar is the place where I was born.

In the examples above we can see that the adjective describes the noun clause is in front of him (antecedent).For example : Adjective clause Who is sitting over there to explain the noun man. Adjective clause why she did it explain the reason nouns.

Adjective Clause is used to provide information, identity, and other information to noun (antecedent). The Adjective Clause structure is characterized by relative pronouns, namely: who, whom, Whose, which, when, where, why, and that.

    Who : used for people in positions subject (human as subject).
    Whom : used for people in the position of the object (human as object).
    Which : used for objects, either in subject or object position (non-human as subject / object).
    That : used as a substitute who, whom, or which.
    Whose : used for ownership.
    When : used for time.
    Why : used for the cause.

• Adjective clause is divided into two kinds, namely:
  Important (defining) adjective clause, adjective clause is that is important information for the antecedent.
  Example : That Bob's brother (WHO) lives in New York is an actor.
  Meaning : Bob has more than one brother.
• Unimportant (undefining) adjective clause, adjective clause is that the information that is important for the antecedent.
  Example : Bob's brother, WHO lives in New York is an actor.
  Meaning : Bob has only one brother.

Example of Adjective Clause

1. The student who doesn’t study seriously will not pass.
2. The girl whom I introduce to you last week is my student
3. The animal which runs quicly named lion.
4. The student whose hat is yellow is lazy student
5. My English teacher is the man who Is standing near the pillar.

Example a part of article containing the adjective clauses (underline,bold,italic)
         Computers do allow students to expand their learning beyond the classroom, but the distance learning is not a utopia. Some businesses, such as Hewlett Packard, do have mentoring programs with children in the schools, but those mentoring programs are not available to all students. Distance learning has always been a dream of administrators, eager to figure out a cheaper way to deliver education. They think that little Eva and Johnny are going to learn about Japanese culture or science or algebra in the evening when they could be talking with their friends on the phone or watching television. As education critic Neil Postman points out, these administrators are not imagining a new technology but a new kind of child: "In [the administrator's] vision, there is a confident and typical sense of unreality. Little Eva can't sleep, so she decides to learn a little algebra? Where does little Eva come from? Mars?" Only students from some distant  planet would prefer to stick their nose in a computer rather than watch TV or go to school and be with their friends.

        Their short attention spans, their unwillingness to explore subjects in depth, their poor reading and evaluation skills. Computers also tend to isolate students, to turn them into computer geeks who think cyberspace is actually real. Some students have found they have a serious and addictive case of "Webaholism," where they spend hours and hours on the computer at the expense of their family and friends. Unfortunately, computers tend to separate, not socialize students. Finally, we need to think about who has the most to gain or lose from computers in the schools.

        Are administrators getting more students "taught" for less money? Are big companies training a force of computer worker bees to run their businesses? Will corporate CEO's use technology to isolate and control their employees? Like all cults, this one has the intention of enlisting mindless allegiance and acquiescence. People who have no clear idea of what they mean by information or why they should want so much  of it are nonetheless prepared to believe that we live in an Information Age, which makes every computer around us what the relics of the True Cross were in the Age of Faith: emblems of  salvation. 

Questions and Answers of the excercises

1. Q : I talked to the woman she was sitting next to me
   A : I talked to the woman who was sitting next to me
   
2. Q : I have a class it begins at 08.00 Am
   A : I have a class which begins at 08.00 Am
   
3. Q : The man called the police his car was stolen
   A : The man whose car was stolen called the police
   
4. Q : The building is very old he lives there
   A : The building where he lives is very old
   
5. Q : The woman was ms Silvy I saw her
   A : The woman whom I saw was ms Silvy

Reference :

http://free-english-lesson.blogspot.com
http://eslbee.com/AdjClauses.htm