In ancient times the most important examinations were spoken, not written. In the schools of ancient Greece and Rome, testing usually consisted of reading poetry aloud or giving speeches. In the European universities of the Middle Ages, students who were working for advanced degrees had to discuss questions in their field of study with people who had made special study of the subject. This custom still exists today as part of the process of testing candidates for the doctorate(博士学位). Generally, however, modem examinations are written. The written examination, where all students are tested on the same questions, was probably not known until the nineteenth century. Perhaps it came into existence with the great increase in population and the development of modern industry. A room full of candidates for a state examination, timed exactly by electric clocks and carefully watched over by managers, resembles a group of workers at an automobile factory. Generally, during examinations teachers and students are expected to act like machines. One type of test is sometimes called an "objective" test. It is intended to deal with facts, not personal opinions. To make up an objective test, the teacher writes a series of questions, each of which has only one correct answer. Along with each question the teacher writes the correct answer and another three statements that look like correct answers to students who have not learned the material properly.