Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.

Ever since 1859, when Charles Darwin published his theory of evolution, a desperate race had been on between scientists to discover the evolutionary intermediate between apes and humans. But this so-called 'missing link' was proving very elusive. In 1912, an amateur archaeologist called Charles Dawson said he had found a skull in Barkham Manor, Piltdown, in Sussex, England. At the time, scientists thought the skull was genuine, and that Dawson had indeed discovered the missing link. He became famous almost overnight. Nevertheless, it later transpired that the skull was a forgery, made from a human skull only about 500 years old with its jaw replaced by that of a female orangutan, with the bones stained to make them appear older. It remains unknown, however, who made the skull, and whether Dawson knew it was a fake. Fingers have been pointed not only at Dawson, but at various other scientists and people said to be his enemies, but nobody knows for sure. The motivation for the hoax is also unknown. One theory is patriotism. Given that sensational discoveries of early humans had recently occurred, first in Germany and then in France, and given the patriotic one-upmanship of pre-First World War Europe, huge pressure was on British scientists to show that Britain had also played a major role in human evolution. Piltdown man seemed a godsend in this respect since it made Britain seem to be the birthplace of mankind. Even if patriotism was not the motivation for Piltdown. man, it certainly made it harder for British scientists to see it for the hoax that it was. Indeed, despite its inconsistencies with other early humans discovered in the wake of Piltdown, which would normally have precipitated critical testing much sooner, it was over 40 years before re-examination showed the Piltdown skull to be a fake.

Do you know that many useful things________ by accidents? A. were invented B. is inventing C. invented D. have invented