单选题The word "others" in line 27 refers to

单选题What is the author's main point in paragraph 3?

单选题All of the following are mentioned in the passage as reasons for the increased demand for cotton EXCEPT

单选题Often invisible, always in motion, gas is ______ of matter.

单选题Many dinosaurs were (so much) heavy that they (spent) most of their lives in swamps and shallow lakes (where) water (could support) them.

单选题The Texas Legislature selected Vassar Miller __________ in 1982, and again in 1988.

单选题Technology: Mobile Phone Professor: Okay, everyone, let"s ______. Today I would like to discuss the use of mobile phones. I"m sure most of you ______ your friends using your cell phones. Mobile phones have ______ since their introduction and have advanced ______ in regard to technology. In Korea, many phones nowadays can even be ______ a small mobile TV. Users of cell phones have also ______ the years. In Canada, roughly 69% of people between the ages of 15 and 69 own a mobile phone. The number jumps to 93% in Sweden, where they have the highest mobile phone ownership. We need to ______ the mobile phone has not been accepted by everyone. Some ______ that the radio waves emitted by the phone can ______ your health. Scientists ______ because they have known for many years that radio waves can cause heating of the skin and ______. In fact, people who regularly ______ strong radio waves have ______ and the ability to reason and the ______ over body movements and heart rate. Due to these complaints, safety guidelines for working with powerful radio waves have been introduced. For people like you and I who don"t come in contact with strong radio waves ______, the safe limits are less than those recommended for workers. So what do these findings ______ the mobile phone? Well, mobile phones work ______. As a result, the radio waves they emit are minimal. Although it is not specifically ______, people are still concerned. What"s the bad news? Well, these guidelines are ______ caused by the heating of tissues, such as your ear and head. Don"t worry though, because although mobile phones ______ when we use them, this heat is not powerful enough to cause damage to us. Bear in mind that there is still some reason ______. A group of scientists ______ from mobile phones. They found that ______ there is no evidence of negative health effects caused by radio wave radiation. However, they were ______ the mobile phone "safe" due to the need for more research. They also found that radio waves may ______ but this may not necessarily lead to any particular harm to the adult mobile user. This cannot be said for small children though. Because ______ are still growing, it is easier for radio waves from a mobile phone to enter their heads and their skin ______ more radiation compared to adults. The scientists concluded that children should only use mobiles for short, important calls. The scientists also recommended that ______ mobile phone manufacturers publishing the amount of radio wave energy that each handset transmits to the human body. This would better ______ any possible risk. Although there is no evidence of a risk to the health of people living ______, radio wave emissions should be monitored, especially near schools. Another controversial issue regarding mobile phones is whether drivers should be able to ______. I think we can all agree that talking on the phone while driving ______. In order to satisfy critics who still think that mobile phones ______ of radio waves, the hands-free phone has gained support. The hands-free phone has many benefits including the ______ radio wave radiation due to the increase in distance of your head to the handset. Rather than holding your mobile phone against your ear, which ______ radio waves, you can now ______ and still talk to someone with an ear-piece cable. This new solution still has problems. One study found that when the phone is in an exact position and the cable is ______, the ear-piece cable actually directs more radio waves "into the user"s ear. To solve this ______, some ______ might find a shield that can protect them from radio waves useful. By and large, studies have shown that mobile phones do not ______, unless they are driving and talking on the phone at the same time. Moreover, hands-free phones are ______ a cell phone next to your ear. Ongoing research should still be conducted to ______ who may still have some health concerns.

单选题In 1884 Belva Lockwood, a lawyer who had appeared before the Supreme Court, became the first woman was nominated for President of the United States.

单选题The word "prominent" in line 27 is closest in meaning to

单选题Which of the following is true about the human diet prior to the Neolithic period?

单选题Why is "plankton" mentioned in line 17?

单选题In Earth's infancy, its surface was warm enough for life ____ the young Sun was fainter than it is today.

单选题Geraldine Farrar, (who) debuted as (an) opera singer in 1901,later appeared (both) on stage and in several silent (film).

单选题The Fundamental physical (principle) of photography is that (light falling) on the grains (of certain) insoluble silver salts produces small, (invisibly) changes in the grains.

单选题Although legend has it that the Pilgrims first set foot in America on Plymouth Rock in 1620, ------ documentary evidence confirming this.

单选题In the orbit of a planet around the Sun, the point closest to the Sun is called it the perihelion.

单选题The word "Various" in line 21 is closest in meaning to

单选题It can be inferred from paragraph 3 that chipmunks do not aid in the dispersal of oak trees because

单选题Which of the following is a significant way in which Impressionists were different from the artists that preceded them?

单选题The Medicare program (was established) in 1965 to (helping) elderly United States (citizens pay) the increasing (cost of) health care.