The GRE test consists of 3 parts :-
1. General Test
2. Subjective Test
3. Writing Assessment
4. Qualifying Tests

General Test
The General Test measures verbal, quantitative, and analytical skills that have been acquired over a long period of time and that are not related to any specific field of study. The test consists of three scored sections.

Verbal: 30-minute section (30 questions) — The verbal measure tests your ability to analyze and evaluate written material and synthesize information obtained from it, analyze relationships among component parts of sentences, and recognize relationships between words and concepts.

Quantitative: 45-minute section (28 questions) — The quantitative measure tests your basic mathematical skills and your understanding of elementary mathematical concepts, as well as your ability to reason quantitatively and solve problems in a quantitative setting. The content areas included in the quantitative sections of the test are arithmetic, algebra, geometry, and data analysis. These are content areas usually studied in high school.

Analytical: 60-minute section (35 questions) — The analytical measure tests your ability to understand structured sets of relationships, deduce new information from sets of relationships, analyze and evaluate arguments, identify central issues and hypotheses, draw sound inferences, and identify plausible causal explanations. Questions in the analytical section measure reasoning skills developed in virtually all fields of study. No formal training in logic or methods of analysis is needed to do well in these sections.

Subject Tests
The GRE Subject Tests are designed to help graduate school admission committees and fellowship sponsors assess the qualifications of applicants in specific fields of study. The tests also provide students with an assessment of their own qualifications.

Scores on the tests are intended to indicate students' knowledge of the subject matter emphasized in many undergraduate programs as preparation for graduate study. Since past achievement is usually a good indicator of future performance, the scores are helpful in predicting students' success in graduate study. Because the tests are standardized, the test scores permit comparison of students from different institutions with different undergraduate programs. For some Subject Tests, subscores are provided in addition to the total score; these subscores indicate the strengths and weaknesses of individual student's preparation, and they may help students plan their future studies.

Subject Tests are currently available in 8 disciplines.
Biochemistry, Cell and Molecular Biology Literature in English
Biology Mathematics
Chemistry Physics
Computer Science Psychology

Writing Assessment
The GRE Writing Assessment is offered separately from the GRE General Test and GRE Subject Tests. It is available year round at all ETS-authorized computer-based testing centers.

The Writing Assessment substantially expands the range of skills assessed by the GRE General Test and the GRE Subject Tests, including your ability to

The assessment consists of two analytical writing tasks: a 45-minute "Present Your Perspective on an Issue" task and a 30-minute "Analyze an Argument" task. The "Issue" task states an opinion on an issue of general interest and asks test takers to address the issue from any perspective(s) they wish, as long as they provide relevant reasons and examples to explain and support their views. The "Argument" task presents a different challenge: it requires test takers to critique an argument by discussing how well reasoned they find it. Test takers are asked to consider the logical soundness of the argument rather than to agree or disagree with the position it presents. The two tasks are complementary in that one requires test takers to construct their own arguments by making claims and providing evidence supporting their positions on the issue, whereas the other requires them to critique someone else's argument by assessing its claims and evaluating the evidence it provides. Actual test questions are selected from the published pool of Issue and Argument Topics

For more detail: www.gre.org