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.
Swans are among the most beautiful of North American waterfowl and have always enjoyed the admiration and even the protection of bird lovers. Of the six species in the swan genus, only two are native to North America. The trumpeter swan, the largest of the group, breeds in the northern United States and Alaska, and was nearly wiped out during the nineteenth century craze for elaborately feathered hats. The whistling swan, which winters in large flocks on the Chesapeake  Bay, has recently been renamed the tundra swan because it breeds and summers on the northernmost tundra regions of the continent.
Recently, populations of mute swans - an exotic species introduced to North America from Europe in the early 1900s - have begun increasing by an alarming 30 to 40 percent annually in some states. Most wildlife biologists today believe the majestic white creatures, with their tendency to destroy a pond's plant life and drive away native waterfowl, might create havoc on the scale of the gypsy moth, starling, or English sparrow.
Both native species of swans are wild and require large areas of uninhabited summer ground for nesting and feeding. Mutes, however, semi-domesticated and accustomed to people, can nest in pairs of as many as three or four on one small coastal pond, which can burden delicate and environmentally essential brackish ponds.
 
It can be inferred from the passage that the author                           .
A.prefers trumpeter swans
B.is concerned about mute swans
C.is a wildlife biologist
D.approves of all swans

Các câu hỏi liên quan

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.
Diamond value is based on four characteristics: carat, color, clarity, and cut. A diamond’s size is measured by carat weight. There are 100 points in a carat and 142 carats in an ounce. Each point above 1 carat is more valuable than each point below 1 carat. Thus, a stone that weighs more than 1 carat is more valuable per point than a stone that is smaller than 1 carat.
The scale used for rating a diamond’s color begins with “D,” which means the stone is absolutely colorless and therefore most valuable. “E” and “F’ are almost colorless. All three are good for investments. A stone rated between “G” and “J” is good for jewelry. After that the stones take on a slightly yellowish color, which gets deeper as the grade declines.
The clarity of a stone is determined by its lack of carbon spots, inner flaws, and surface blemishes. While most of these are invisible to the unaided eye, they do affect the diamond’s brilliance. For jewelry, a diamond rated VVS1 (very very slight imperfections) is as close to flawless as one will find. After that the scale goes to VVS2, VS1, VS2, SI1, SI2, I1, I2, and so on.
The final characteristic is cut. When shaped (round, oval, emerald, marquise, pear, or heart), the diamond should be faceted so that light is directed into the depths of the prism and then reflected outward again. A well-cut diamond will separate the light into different colors when the light is reflected. Only stones of similar shape should have their reflective qualities compared, as some shapes are more reflective than others. For example, the round shape is the most reflective.
Even though they affect a diamond’s brilliance, slight carbon spots, inner flaws, and surface blemishes _________ .
A.lack imperfections           
B.are rated VVS1
C.cannot be seen with the naked eye
D.can make a diamond more valuable