托福听力每日一练第41天：（2004年5月）
演讲听写训练1：
Today let’s consider the neutrino and the resolves of some experiments down in the 1995 at the Los Alamos national laboratory in New Mexico, which bear on the neutrino. These resolves suggest that this little particle does indeed have mass that tiny bet to be sure but measurable by the very sensitive instruments of that lab. The neutrino’s origin has always been an interesting case, though a case not unusual in the history of physics. As you know, ordinarily scientific observation precedes scientific theory. Ocean tides were observed, ocean tides were explained; gravity is observed, gravity is explained. However, let’s consider what happened in the neutrino’s case. When the neutrino was proposed over sixty years ago, it was a convenient fiction. Scientists had not observed such a particle nor even as a fact. So what let them to conceive of this imaginary object? They had been writing equations about neutron decay in which the energy amounts on each side of their equations were unequal. In order to keep this energy amounts the same on both sides of the equations, they added little particle named neutrino and gave it precisely enough energy to balance the equations and the loan be hold years later. About thirty-five years ago real neutrinos were found. Now we have the more recent developments. Originally, the neutrino was thought not to have any mass at all. But Los Alamos experiments seem to disprove this premise. They indicated that neutrinos do have mass-about one-millionth the mass of electron.
演讲听写训练2：
The forests of New England constituted both are resource and barrier for the first British settlers who reach these shores. In addition to the maples, firs, oaks and birches were white pines whose scientific name is Pinus strobus. These white pines were straight and tall, perfect for use as masts on the sailing ships of the time. Britain had used up its supply of mast trees, so is eager for this product of its young colony. By the first load of masts reached Britain in 1634 and Britain was marveled the size of the trees, which had diameters of up to 4 feet at the wide end. For every yard of mast height, the body end needed to be one inch in diameter. In1705, Britain passed a law stating that all white pines over 24 inches at the body end were reserved for the use of king’s navy. Such trees were marked by blazing the king’s arrow symbol on the tree with three cuts of the hatchet. These trees were selected by the surveyor general, whose work often met with resistances of colonists.
演讲听写训练3：
Now the Australia jumping spider as you can image got its name for its ability to leap. But it can swim too. What’s most interesting though is its ability to use try and error tactics when solving problems. Now the jumping spider attacks and eats other spiders. It’ll sit at the edge of another spider's web and attract the spider by tapping out different signals to mimic the struggles of a trapped insect and it’ll keep changing the signals till successfully lured its prey out. Well, to see if the jumping spider could apply the same problem solving technique, try and error to unfamiliar situations, scientists conducted an experiment. They field a trap full of water and then put some sand in the middle, like an island. In between the island and the edge of the trap, they put a rock. When they put the spider on the island, some tried jumping to the rock, and some tried swimming. All the spiders that successfully reached the rock either by jumping or by swimming use the same method to make it from the rock to the edge of the tree. If the spider failed to reach the rock, it was placed back on the island, but the next time they try to leave, spiders did opposite of whatever didn’t work the first time, leaping if it had swum, or swimming if it had leaped. So we see the spiders using the same try and error in crossing the water as they used in hunting.
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