21- We can assume from the passage that the Sahara may prove useful in the future because…… . A) It is growing and expanding towards the south
B) there are large amounts of necessary minerals there
C) it may be uniting with Nigeria and other countries
D) it may be used to irrigate neighbouring countries
E) it will probably continue to remain uninhabited
Relativity is the name for two theories of physics presented by Albert Einstein in 1905 and 1915 respectively, as the Special and General Theories of Relativity. Through them he showed that speed and position are relative things and that there are no absolute measurements for time and space. He also stated that matter and energy are interchangeable, a concept that has had considerable bearing on the development of nuclear physics. In this century, Einstein's Theories of Relativity have revolutionised ideas about the nature of matter and the universe, as Sir Isaac Newton's laws of gravity had done to scientific thinking two centuries earlier.
22- According to the passage, Einstein's theories state that…………. . A) there are no definite ways to determine time or location
B) things can be measured by either special or general means
C) how fast something goes, and where it is, are fixed values
D) before 1905, scientists looked at the universe in the wrong way
E) there's simply no point in worrying about either time or space
23- As stated in the passage, Einstein claimed that…………. . A) matter and energy are really exactly the same thing
B) nobody really knows the true nature of matter
C) nuclear energy is definitely the best form of energy
D) the true nature of energy doesn’t really matter
E) matter and energy can be changed into each other
24- The passage suggest that Newton and Einstein ………… . A) greatly influenced each other and their respective theories
B) have each had profound influence on modern scientific thought
C) were respectful to each other's theories
D) suffered a great deal due to their revolutionary ideas
E) offer distinct theories in direct contradiction to each other
Native Americans are often called “Indians”. This is one result of Columbus’s mistaken belief that he had landed in India. His successors passed down many other inaccurate descriptions of the Native Americans. They were described as savages, though it was whites who slaughtered hundreds of thousands of them. They were called lazy, although it was whites who forced them to give up their traditional occupations. These false ideas about Native Americans were strengthened by the ways whites described themselves. White settlers were known as .'Pioneers' though they were really invaders and thieves; when they stole the Native Americans' land, it was called "home steading". not robbery.