单选题(Ever since) the world (began), nations (have difficulty) (in keeping) peace with their neighbors.

单选题From the passage, we can conclude that

单选题Many animals that lived thousands of years ago are now .

单选题He began by showing us where the country was and went on______us about its climate.

单选题These books are designed to ______ children.

单选题The more (frequent) the child expresses his (interest) in (an) activity, the stranger (it) will become.

单选题"Helicopter parenting" describes a style of raising children where parents are over-protective and do too much. The term was used for the first time in the late 1960s. It describes parents who watch over their kids like a helicopter. Today, modern technology allows these helicopter parents to watch over from even far away. They can give their children directions at any moment from anywhere. Author Julie Lythcott-Haims wrote a book titled How to Raise an Adult . In her book, she gives readers a closer look at this parenting style. "Over-parenting", she says, "comes in three types: the first is the over-protective parents who think the world is scary and unsafe and unpredictable. And therefore, I must protect and prevent. The second type is the over-directive type—the parent who says, I know best what leads to success and you will do as I say. You"ll study these topics, do these activities and you will be highly achieving at all of it. The third type is the concierge (看门人)—the parent who just wants to make life smoother—from waking their kid up, to keeping track of their deadlines, to making sure they haven"t forgotten anything, to even doing the homework for the kid." Julie Lythcott-Haims says she experienced the effects of helicopter parenting firsthand when she worked as dean of first-year students at Stanford University. The incoming students were very smart and accomplished on paper. But many were unable to take care of themselves. "They were turning to parents constantly for guidance, for problem solving, to have them make the choice about something." Often times, Lythcott-Haims had to remind those parents that their kids were old enough to take care of themselves.

单选题Consumers should do ______ than simply complain about the poor quality of goods.

单选题There (are) two kinds of (computers) in this country, both of (them) are widely (used) today.

单选题No sooner had they got off the train (　　)it started moving.

单选题Since the beginning of history, man has been fascinated by the idea of living for ever, of winning the fight against death and disease. So far, this has only remained a dream, though a very powerful one. Many people have wondered whether it would be possible to find a way to preserve human bodies, and what would be the best way to preserve human bodies. It has long been known that meat or fruit can be kept fresh for long periods by freezing; in ancient China, for example, food was stored with ice to keep it fresh. This method could also be useful for preserving humans, and in fact many people have explored this possibility. However, most living beings that exist under warm conditions die when frozen. This is because of the harmful effects of freezing ice crystals (晶体), which are not only larger than the volume of the water originally in the cells, but also form sharp cutting shapes that harm the cells. In the 1940s, Dr. B.J. Luyet and a group of scientists in England were working on the problem of freezing cells without damaging them. Since the harm caused by ice crystals was the main cause of the damage, Luyet suggested removing some or all of the water from the cells before freezing them. Using living cells from chicken, Luyet and his assistants discovered that they could partly dry the chicken cells, using a mixture of the white part of an egg and glycerin (丙三醇), a clear, thick liquid made chiefly from fats and oils. Some success was obtained. The chicken cells were dried, frozen for a period of time, and then carefully unfrozen. Almost all the cells recovered when they reached normal temperatures. Since then, the cooling of whole animals to a temperature very much below freezing point for later unfreezing has become more of a possibility, and the glycerin method would probably be used to accomplish this. When this can be done completely and successfully, science will have moved much closer to its aim of freezing and storing incurable patients until the day they can be cured.

单选题It’s getting late. We __________leave now, or we’ll miss the last bus.

单选题It has been said that in no country __________ Britain can one experience four seasons in the course of a single day.

单选题More than one __________ the food in the canteen.

单选题His parents died when he was young so he was ______ by his aunt.

单选题Speaker A: If you like, I could help you paint (刷油漆) the room tomorrow. Speaker B.__________

单选题(However good) (are my paintings), I am (conscious) that they may (leave) much to be desired.