My dear old friend Sebastian used to tell me that he had something of a sliding scale regarding the musicians to which he could listen. For him, Bach was the most celestial of musicians, and he could listen to him for an eternity without ever being wearied. Mozart was likewise favorably judged, though Sebastian said that he could only endure his music for approximately three to five hours at a time. When it came to Richard Wagner, however, my dear friend was quite unable to bear the intensity of the composer’s works. In stark contrast to his great patience and love for the music of Bach, he could spend little more than five minutes listening to compositions by Wagner.

Based on its context in the selection above, what does the expression "sliding scale" (underlined) mean?

Adapted from Cowboy Songs and Other Frontier Ballads by John A. Lomax (1910)

The big ranches of the West are now being cut up into small farms. The nester has come, and come to stay. Gone is the buffalo and the free grass of the open plain—even the stinging lizard, the horned frog, the centipede, the prairie dog, the rattlesnake, are fast disappearing. Save in some of the secluded valleys of southern New Mexico, the old-time round-up is no more; the trails to Kansas and to Montana have become grass-grown or lost in fields of waving grain; the maverick steer, the regal longhorn, has been supplanted by his unpoetic but more beefy and profitable Polled Angus, Durham, and Hereford cousins from across the seas. The changing and romantic West of the early days lives mainly in story and in song. The last figure to vanish is the cowboy, the animating spirit of the vanishing era. He sits his horse easily as he rides through a wide valley, enclosed by mountains, clad in the hazy purple of coming night,—with his face turned steadily down the long, long road, "the road that the sun goes down." Dauntless, reckless, without the unearthly purity of Sir Galahad though as gentle to a woman as King Arthur, he is truly a knight of the twentieth century. A vagrant puff of wind shakes a corner of the crimson handkerchief knotted loosely at his throat; the thud of his pony's feet mingling with the jingle of his spurs is borne back; and as the careless, gracious, lovable figure disappears over the divide, the breeze brings to the ears, faint and far yet cheery still, the refrain of a cowboy song.

The mood of the passage is best described as __________.

"The Dangers of Sugar" by Daniel Morrison (2014)

Sugar is a highly addictive substance that plays a dangerous role in the health and well-being of people around the world. It is particularly threatening to American health, as it is placed in everything from carbonated sodas to beef jerky and vegetable juice. The average American consumes seventy-five pounds of sugar every year—that is roughly the weight of a elementary school child. Many health experts believe that sugar is the number one contributing factor in the high rates of obesity, heart disease, and diabetes that can be found in the contemporary United States.

The author’s tone in this passage could best be described as __________.

Adapted from Scientific American Supplement No. 1157 Vol. XLV (March 5th, 1898)

"Artists" of the variety stage and the circus are always trying to find something new, for the same old trapeze performances, trials of strength, performances of rope dancers, etc., have been presented so many times that anyone who invents an entirely new trick is sure of making a large amount of money out of it; the more wild and dangerous it is, the better. Anything that naturally stands on its feet but can be made to stand on its head will be well received in the latter attitude by the public. Some such thought as this must have been in the mind of the man who conceived the idea of riding a bicycle on the ceiling instead of on the floor. The "trick" originated with the Swiss acrobat Di Batta, who, being too old to undertake such a performance himself, trained two of his pupils to do it, and they appeared with their wheel in Busch Circus in Berlin. The wheel, of course, ran on a track from which it was suspended in such a way that it could not fall, and the man who operated it used the handle bar as he would the cross bar of the trapeze. One would think that the position of the rider was sufficiently dangerous to satisfy any public, but the inventor of the trick sought to make it appear more wonderful by having the rider carry between his teeth a little trapeze from the crosspiece of which another man hung. Different colored lights were thrown on the performers as they rode around the ceiling, and at the end of the performance first one and then the other dropped into the safety net which had been placed about sixty feet below them.

Circus performers are primarily characterized by their ability to __________.