单选题A cardinal role for (players) of the lute, (a stringed) instrument, (are) that every note is sustained for (as long as) possible.

单选题Globally, the 1990’s stood out as the warmest decade for what we have weather records.

单选题Although Alaska ia the state in the United States with the largest area, Texas is the one that is divide into the largest number of counties.

单选题It can be inferred that flood plains, deltas, and stream channels (lines 13-14) are similar in which of the following ways?

单选题[此试题无题干]

单选题The task of feeding larvae is mentioned in thepassage to demonstrate

单选题It can be inferred from the passage that brain size is assumed to

单选题Mutiny of a ship's crew against the captain (signifies) the breakdown of the (obedience) and (discipline required) to deal effectively (to) perils at eat.

单选题Sports Engineering: Tennis Professor: ______, how many people here like sports? Good, that"s more than half. Now, how many of you believe ______ in sports? Interesting. Not many of you believe in luck. Okay, how many people believe that ______ who generates power in sports? Oh, my. Most of you believe this. Well, I am here to ______ this belief. Actually, to be fair, many factors ______ any sport, but skill is just one of them. Today, I would like to discuss the role that science plays in sports. Principles ______, physics, math, and sports nutrition relate to sports such as baseball, cycling, cricket, tennis, and skateboarding to name a few. Let"s take tennis as an example. I"m sure you have ______ great American tennis players such as Andy Roddick, who ______ the fastest serve for a man, an incredible 245 km/h as of 2004, and Venus Williams, the fastest serve for a woman at 203 km/h. Well, it has been suggested that skill only played a part in their serve. In fact, ______ their tennis racket! Starting in the 1970s the tennis racket"s ______. Following this, different materials were used to design the racket. Perhaps the most significant contribution is a ______. In fact, many professional tennis players use rackets with ______. Now the graphite can be ______ such as boron and titanium to produce even stronger and lighter rackets. These new designs mean players like Roddick and Williams can ______ than ever before. It wasn"t just the speed and accuracy the new material improved, though. When wood used to be used for the frame of the rackets, the heads were smaller and ______ because the frames weren"t strong enough to ______. Now with material like titanium, the frame is stronger but not heavier. ______, they can now be longer ______. As well, because the strings are tighter, they allow for more control and accuracy. The bonus to this is that even when the player unskillfully hits the ball ______, it will still ______ because the frame is larger, allowing the longer strings to work together. ______ of the tennis racket also ______ where twisting is concerned when the ball is not hit in the dead center of the racket. I mentioned that the new materials ______, but what does this mean for the players? Well, it means that stars like Roddick and Williams are able to use a ______ a lot easier than players before the 1970s. Because the new rackets don"t require skill for the ball to ______, modern players don"t have to ______ all the time. What about the next generation of tennis players? What can they look forward to? Well, several engineers are trying numerous combinations of different materials and designs to ______ of rackets. For example, some of the newest rackets have a tip that is heavier than the handle and longer rackets are ______ these days. There has even been talk of using ______, but they haven"t caught on with professional players yet. We need to give some credit to the players because they are using their new rackets ______. A ______ has recently been used by today"s tennis stars. The topspin is created by hitting the top surface of the ball with brilliant power and precision, which ______. This requires skill because there is a certain way to ______ the tennis racket. The best grip to use in order to achieve the topspin is the Western grip. ______, the Western grip helps keep the racket head stable when the ball is ______. The only problem with the Western grip is it is difficult to ______. For this reason, not all players want to ______ Eastern grip. Another traditional move ______ has also been improved with a new grip these days. Many players, particularly the women, are using two hands for the move. Not only is it easier to produce topspin with both hands, but it also allows the players to ______. I hope this discussion has ______ the sport of tennis and how science has ______. It is clear that while Venus Williams is ______, we mustn"t forget to thank her racket!

单选题Mathematics is a tool that can help solve problems and lead to new developments in other fields, such as space flight, medical, and architecture.

单选题In the 1820’s physical education became_______ of the curriculum of Harvard and Yale Universities.

单选题One of the basic principles of wildlife conservation involves ______ adequate natural food and shelter to maintain populations of each species in a given habitat.

单选题Each (of functions) (of the body), even thinking, requires (the expenditure) (of energy).

单选题of countries belonging to GATT approved the agreement yesterday in Geneva.

单选题The word "sole" in line 6 is closest in meaning to

单选题._______ the president is going to say in his speech tonight will affect all of us.

单选题Narrator Listen to a talk between two students. Now get ready to answer the questions. You may use your notes to help you answer.

单选题The word "It" in line 14 refers to

单选题Their products are known not only for their low price, __________ for their high quality.