Section III: Cloze (5 points)

　　Directions: For each numbered blank in the following passage, there are four choices marked A, B, C, and D. Choose the best one and mark your answer on the ANSWER SHEET 1.

　　Energy equals mass times the speed of light squared. This is the famous equation of Albert Einstein. It 41 to the category of the theory of relativity, and it equates energy with mass. All things are made up of atoms. When 42 of an atom travels at almost the speed of light, and we put more energy into it to 43 the speed, it begins to increase in mass. The energy that makes it travel fast cannot make it travel beyond the speed of light—nothing 44 light can travel that fast—so the energy goes into the thing itself and increases its mass. Energy 45 into mass.

　　Why is the theory called the theory of relativity? A thing that is relative depends upon something else to identify it or to define it. In relativity theory we identify or define mass, time, and length 46 to the speed of light.

　　When something is at rest, it looks ordinary in length. However, when it travels at almost the speed of light, it becomes 47 . Time also changes. However, the change in time is 48 to the change in length. The length of a thing becomes short but time becomes long.

　　If you want to 49 young, relative to a friend, take a trio in a spaceship that travels at almost the speed of light. And, although time and heartbeat 50 ordinary to you in the spaceship, when you return, look at your friend: Relative to you, he or she is old.

　　41. A. prefersB. relatesC. belongsD. adheres

　　42. A. partB. formC. portionD. fraction

　　43. A. increaseB. reduceC. decreaseD. shrink

　　44. A. thatB. whichC. butD. thus

　　45. A. changesB. becomesC. shiftsD. turns

　　46. A. relatedB. relationC. relativeD. relationship

　　47. A. low B. shortC. wideD. long

　　48. A. equalB. similarC. oppositeD. subject

　　49. A. keepB. stayC. remainD. reserve

　　50. A. takeB. showC. appearD. seem