Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks

School exams are, generally speaking, the first kind of tests we take. They find out (16) ______ much knowledge we have gained. But do they really show how intelligent we are? After all, isn't it a fact that some people who are very successful academically don't have any common sense?

          Intelligence is the speed at which we can understand and react to new situations and it is usually tested by logic puzzles. (17) ______ scientists are now preparing advanced computer technology that will be able to “read” our brains, for the present, tests are still the most popular ways of measuring intelligence.

          A person's IQ is his intelligence (18) ______ it is measured by a special test The most common IQ tests are run by Mensa, an organization that was founded in England in 1946. By 1976 it had 1,300 m.embers in Britain. Today there are 44,000 in Britain and 100,000 worldwide, (19) ______ the US.

          People taking the tests are judged in relation to an average score of 100, and those (20) ______score over l48 are entitled to join Mensa. This works out at 2% of the population.

They find out (16) ______ much knowledge we have gained.