题目内容
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The underlined word "stumble" in Para 3 means ______.
A．fall
B．speak in a hesitating way
C．walk with heavy movements
D．be shy
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更多“The underlined word "stumble" in Para 3 means ______.A．fallB．speak in a hesitating wayC．wa”相关的问题
B．the temperature of the air
C．humid air
D．the process in which water vapor changes to liquid water when the air is cold enough
B．and so is Dad
C．and Dad has, too
D．and Dad also loves Mom
B．nevertheless
C．therefore
D．seldom
A、black and white
B、green and red
C、white and blue
D、yellow and red
First, then let's look at the meanings of the terms "seminar" and "tutorial". Nowadays it's becoming more and more difficult to draw a precise distinction between the meanings of the two words that all lecturers would be willing to accept. The traditional differences which are still accepted by many lecturers are firstly the size of the group and secondly, and perhaps more importantly, their purpose.
A tutorial was usually for a small number of students, say, between two and five, whereas a seminar was attended by a large group, say, between ten and fifteen. In a tutorial, a lecturer or tutor adopted the role of the expert and asked and answered questions related to his most recent lecture. In short, the tutor took the lead; he in fact "tutored".
The purpose of the seminar, on the other hand, was to provide an opportunity to discuss a previously arranged topic. Often one student presented a paper; that is, gave a short talk which served as an introduction to a more general discussion. The other students may have been asked to read a number of chapters of a book, related to the talk, so as to be in a better position to participate in the discussion.
(29)
A．A librarian.
B．A monitor.
C．A Chairman.
D．A lecturer.
A．Y
B．N
C．NG
A．＄1 million.
B．＄10,000.
C．＄98,000.
D．＄22,000.
Directions: In this section, you will hear 3 short passages. At the end of each passage, you will hear some questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A, B, C and D.
(27)
A．They were driven by steam engines.
B．They were pulled by riders themselves.
C．They were pulled by animals or humans.
D．There were totally unusable.
Rusty Rhea sighs wistfully as he talks about the beauty and peace of standing amid a grove (小树林) of deep green hemlocks in Appalachia, some of them up to 160 feet (50 meters) tall and more than 500 years old.
"This is a very special tree," said Rhea, an entomologist for the U.S. Forest Service's Forest Health Protection program in Asheville, North Carolina. "I was brought up here, and I don't want to see another species go by the wayside."
The evergreen trees, a hallmark of southern Appalachia's national parks, are under attack by an invasive insect barely visible to the eye but potent enough to fell the giants of the eastern United States' old-growth forests.
Already the tiny bug from Japan, known as the hemlock woolly adelgid (HWA), has killed upward of 95 percent of the hemlocks in Virginia's Shenandoah National Park. Now they are making their way through the half-million-plus-acre (200,000-plus-hectare) Great Smoky Mountains National Park in North Carolina and Tennessee.
The hemlocks shade streams, keeping water temperatures just right for brook trout(鲑鱼) and other fish. They also house birds such as the black-throated green warbler, solitary vireo, and northern goshawk, all three of which mainly shelter in stands of hemlock trees.
Because of the insect's broad impact on the entire ecosystem of southern Appalachia, HWA stands to cause wider damage than the American chestnut blight(枯萎病) of the early 1900s. That fungus from Europe killed off the once dominant chestnut trees from the northeast United States to the southern Appalachian Mountains.
In addition, a species related to HWA, the balsam woolly adelgid, has already killed about 90 percent of the mature Fraser fir trees in the Smokies.
Acting Quickly
HWA arrived in the U.S. Pacific Northwest via nursery plants from Japan in 1924. By 1951 the tiny invader had been found in Virginia. Since then the insect has spread to more than 15 U.S. states.
The key to killing the HWA is to catch it early and act quickly. It's already well established in the Great Smoky Mountains, where Rhea and others are trying to stem the spread of the bugs.
HWA multiply quickly: All of the insects are females that reproduce asexually (无性地), laying several hundred eggs a year. When they get to the nymph, or crawler, stage, they are dormant from about June until October, after which they emerge and establish themselves on trees.
Winds and birds and other animals spread the crawlers through the forest.
HWA crawlers feed on the new growth of hemlocks by piercing the twigs that hold the branches, sucking the sap, and injecting toxic saliva. The needles turn from a deep green to a grayish green and eventually die, depriving the tree of nutrition from photosynthesis.
An infected tree usually dies within five years of initial attack. Infection is signaled by either a white, cottonlike material that appears along a tree's twigs or by the "baldness" of a tree's upper branches.
Plans of Attack
In the Pacific Northwest the hemlocks seem to be tolerant of the creatures' feeding, and in the cold northeast, winters seem to keep them at bay. But in the warm southeast, with weather approximating that of the insects' native Asian homes, they thrive.
Chemical sprays--such as insecticidal soaps and horticultural oils as well as trunk or soil injections--have helped to kill some of the HWA infestations.
years at most. These methods can't be used conveniently or safely in remote areas or near the streams where hemlocks grow thickly.
Long term, the best way to control the pests appears to be releasing other insects that feed exclusively on HWA. Scientists have studied HWA in Japan and China and identified three such species.
A．Y
B．N
C．NG
A．Objective.
B．Ironical.
C．Approving.
D．Enthusiastic.
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