单选题The word "littered" in line 22 is closest in meaning to

单选题The word "depict" in line 2 is closest in meaning to

单选题. Wood from the ash tree becomes extremely flexibly when it is exposed to steam. A B C D

单选题The author uses the term "Ironically" in line 29 to indicate that a weather map's appearance

单选题Astronomers use photography and sighting telescopes to study the motions of all of the bright stars and many of the faint one.

单选题Because it is often dependent of the conditions of crystallization, the composition of the minerals in a rock can be important in determining the rock's geologic history.

单选题Blood To do its job properly, blood must travel continually around the body. The pumping heart forces blood around the circulatory system to constantly change the fluid surrounding the living cells so that fresh supplies of oxygen and food are brought in as fast as they are used up and poisonous end-products are discarded. The arteries carry blood to every organ of the body, such as the liver, the stomach, the kidneys and the intestines. The liver and kidneys play a vital role in the blood system. Many of the chemical activities carried out within the body result in toxic byproducts. These substances diffuse into the lymphatic system and are carried off into the plasma. When they eventually reach the kidneys, a large proportion of this noxious waste is excreted through the outer organs. The blood passes regularly through the liver and kidneys, picking up nutrients from the former and recycling the waste through the latter. While the kidneys acts as a flushing device for food residues, the liver is mainly a storage system. Only a select amount of nutrients is transferred from the liver to the blood, depending on the body"s immediate need. The rest is stored in the liver until it becomes necessary. The arteries get smaller and smaller as they pass through the various organs and tissues. The smallest vessels are the capillaries. It is through the thin walls of these capillaries that the body cells get their food and oxygen and release their waste. The capillaries join up again to form veins. Blood flows through the veins back to the heart. The arteries have much thicker wails than the veins to withstand the pressure of blood coining directly from the heart. There is little blood pressure in the veins. The action of the muscles of the body helps to massage blood through the veins, and the valves in the vein walls prevent blood in the veins from flowing the wrong way. When blood returns from the veins, the heart pumps it to the lungs. There it gives up carbon dioxide and takes in oxygen. After being refreshed, the blood returns to the heart and is again pumped out to all parts of the body through the arteries. This double flow of fresh blood from the heart to various parts of the body, followed by the transfer of used blood first to the lungs then back to the heart, is called double circulation. The continuous double circulation of the blood system can be measured my means of external devices. Heart monitors are used to record a person"s systolic or diastolic pressure, as the two main components of the double circulation system are termed. There is a healthy range for each blood pressure measurement, which depends on an individual"s age, diet and activity. Strenuous activities are known to temporarily increase blood pressure above the usual top limit. Another sign of increased cardiovascular activity is the bulging of the vein walls during exercise. Contrary to popular belief, this slight enlargement of the veins is not caused by higher blood pressure but rather by enzymatic activity. When more blood is pumped through the system, capillaries dilate and release enzymes to facilitate better arterial flow. The enzymes get into the muscles, and this hardening of the muscles pushes the veins towards the skin giving them a bulging appearance. Glossary circulatory: relating to circulatory system or to circulation of the blood plasma: the fluid part especially of blood lymph, or milk that is distinguished from suspended material capillary: one of the minute blood vessels that connect arterioles and venules artery: a blood vessel that carries blood from the heart to the body

单选题The (poor )condition of (prisoners are ) what (concerned) Dorothea Dix, an American social worker and (director of) a school ill Boston.

单选题(Like) Jupiter (and) Earth, Saturn (is) flattened at (A) poles.

单选题The word "persisted" in line 9 is closest inmeaning to

单选题The Land Ordinance of 1784 divided the western lands belonging to the United States into territories, each to be govern temporarily by its settlers.

单选题Listening7"'Library"

单选题(The) flamingo (constructs) a cylindrical mud nest for (its) egg, which both parents care (for it).

单选题The main (attractive) at Sequoia National Park is thirty-five (groves) of (giant) sequoias,the largest living things in (the world).

单选题The word "hinterland " in line 3 is closest inmeaning to

单选题WhataspectofGPSdoesthetalkmainlydiscuss?

单选题[此试题无题干]

单选题In the diurnal type of tidal oscillation, the alternate rise and fall of sea level, a single high water and a single low water occur ______ tidal day.

单选题1 Some people believe that odors and fragrances affect the body and mind and are capable of healing anxiety, stress, and other sources of disease. Interest in aromatherapy-- and the use of aromatherapy products such as lotions and inhalants--continues to boom. Some popular essential oils and their uses in aromatherapy include lavender and chamomile, which are reputed to ease stress and promote sleep. The scent of jasmine will uplift the mood and reduce depression. Orange eases anxiety and depression and promotes creativity. Peppermint has antibacterial and analgesic qualities, eases mental fatigue, and relieves headaches. 2 However, aromatherapy is not for everyone. For people who suffer from fragrance sensitivity, asthma, or allergies, aromas like perfumes can prompt disabling health problems, including headaches, dizziness, nausea and vomiting, fatigue, difficulty breathing, difficulty concentrating, flu-like symptoms, and anaphylaxis.

单选题1 The Pacific Northwest coast of North America is a temperate rain forest, where trees like the red cedar grow straight trunks more than two meters thick at the base and sixty meters high. Western red cedar is often called the canoe cedar because it supplied the native people of the region with the raw material for their seagoing dugout canoes. These extraordinary crafts, as large as twenty meters in length, were fashioned from a single tree trunk and carried as many as forty people on fishing and whaling expeditions into the open ocean. 2 The Haida people from the Queen Charlotte Islands off British Columbia were noted for their skill in canoe building. After felling a giant tree with controlled burning, the canoe makers split the log into lengthwise sections with stone wedges. They burned away some of the heartwood, leaving a rough but strong cedar shell. They then carved away wood from the inside, keeping the sections below the waterline thickest and heaviest to help keep the canoe upright in stormy seas. To further enhance the canoe's stability, they filled the hull with water and heated it to boiling by dropping in hot stones. This rendered the wood temporarily flexible, so the sides of the hull could be forced apart and held with sturdy wooden thwarts, which served as both cross braces and seats. The canoes were often painted with elaborate designs of cultural significance to the tribe. 3 The Haida raised canoe building to a high art, designing boats of such beauty and utility that neighboring tribes were willing to exchange quantities of hides, meats, and oils for a Haida canoe. These graceful vessels became the tribe's chief item of export. In their swift and staunch canoes, the first people of the Northwest were able to take full advantage of the riches provided by the sea. With harpoons of yew wood, baited hooks of red cedar, and lines of twisted and braided bark fibers, they fished for cod, sturgeon, and halibut, and hunted whales, seals, and sea otters.