题干

图中的玻璃罐模拟池塘生态系统.请回答(1)﹣(4)题.

上一题 下一题 0.0难度 选择题 更新时间:2019-02-17 04:39:07

答案(点此获取答案解析)

同类题2

任务型阅读

    Experts are always advocating the health benefits of biking. And while the barrier to entry is low-pretty much all you need to know to start cycling is how to ride a bike itself-people often ask me if I have any tips for beginner bikers.

    Below, a few things I've learned along the way that help make for a safer and more joyful ride:

    Follow the rules of the road. Brake at yellow lights, stop for pedestrians and maintain a solid distance from cars.____Therefore, never fly through stop signs, approach too close to the front vehicles or shout at cars.

    ____A British doctor recently made headlines when he claimed that wearing a bike helmet is actually more dangerous than traveling without one, but most research suggests otherwise. A full 98 percent of bike commuters (上班族)own a helmet, so you'll be in good company, anyway.

    Make a playlist. Laws against riding with headphones vary from state to state, and it's never proper to listen to music in more than one ear. But cruising around to a soundtrack can be an amazing feeling, so consider buying a wireless speaker you can fix on your frame.  ____

    Know your rights. If you do end up getting into a collision, stay on the scene until the police come.____ Cyclists are too often taken advantage of in bad situations, especially if their injuries don't seem to be apparent.

    Find some friends. As great as it can be to bike alone, zipping down the street in a big group is an equally satisfying experience.____Various bicycle trips are often organized, which provides opportunities to develop friendship among bikers.

A.Be sure to get a helmet.

B.It's necessary you give them an accurate report of the incident.

C.Most cities have enough resources for the cycling community.

D.Most of us will feel it obviously safer to ride on a bike than in a car.

E.Then put together a list of your favorite tunes and get ready to enjoy them.

F.Pushing to the limit not only gives bikers a bad reputation, but also a great danger.

G.It' s comforting to know that whatever I need is nothing more than a bike ride away.

同类题3

阅读理解

    When Carson Palmer, a professional American football player, hurt his arm a few years ago, he took a week off from throwing the football. But in his head, Palmer practiced every day. The following weekend, Palmer had the best game of his life.

    For more than a century, scientists have been trying to understand how this mental training works. In the 1930s, researchers proved by experiment that when you're imagining an action, your brain sends signals to your muscles(肌肉) which are too weak to tighten the muscles but might help train the body to perform. In other words, mental practice might create a pattern in your head, like an inner how-to guide for a particular skill.

    Sports psychologists have conducted hundreds of studies comparing imagined and physical practice for actions. On the whole, the research shows that mental training works. A 2012 study, for example, compared 32 amateur golfers who practiced hitting the balls to another 32 who merely held a golf club in their hands and visualized(想象)their swings. Under the same training rules, both groups improved their skills by getting the ball about 4 inches closer to the hole.

    Visualization has advantages over the real thing: You can do it anywhere, even when injured. It is safe-a major plus for high-risk performers such as gymnasts and surgeons. And you can practice for longer periods of time because you're not restricted by physical tiredness, That's not to say it's easy, we've had Olympic-level athletes sitting in our lab, visualizing the movements for two hours," says Tadhg Macintyre, a sports psychologist at the University of Limerick in Ireland. “When we're done, they're absolutely tired.”

    It doesn't work for everyone, though. "If you're a novice, the effect can be harmful,” warns Macintyre. If you're trying to visualize a free throw, and you don't even know the proper movement, then you're probably going to mentally practice the wrong skill.”