以下来自某人在考场上的回忆 209 words

The professor in the lecture maintains that the three theories regarding petroglyphs are unlikely to be ture.

For the first theory, which proposes that the petroglyphs were left by the Spanish gold-seekers in 1500-1600, the professor points out that the petroglyphs are not of Spanish origins. As archelogists have discovered in an excavation site, the native Americans used the petroglyphs long before the Spanish arrived.

The professor then goes on to invalidate the second theory. Although the native Americans do catch eagles, they usually do so in two common methods. The first one is that hunters hide in a small stone structure, tempt the eagle with a bait and catch it with bare hands. The second one is to locate the eagle's nest and catch the young eagles directly from there. Neither of these two methods would involve the use of petroglyphs.

The third explanation is also opposed. Even though the native Americans were accomplished astronomers, the petroglyphs could not have been related to astronomical observations. If it were the case, the straight lines of the petroglyphs would have pointed to the same direction, since the sun rises and sets at the same place. However, the straight lines of marks point to various direction, proving the third explanation untrue.