The TOEFL test measures the English proficiency of people whose native language is not English, but who need to use the English of North America (American English).There are four parts to the test: Listening, Structure, Reading, and Writing. At present, there are tests for you to practice with the type of material you will find in the Reading and Structure parts of the test.
Listening - Measures your ability to understand spoken American English. You hear short dialogues as well as longer monologues and conversations. You hear each piece once.
Structure - Measures whether you can recognize appropriate language for standard written English and reject errors in grammar or use.
Reading - This section has short, multiple-choice questions on texts usually based on US life and culture.
Writing - An essay. You are given a topic, and often some material to include. You are marked on how well you have done this.