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Trial and error ______ the source of our knowledge.
A．is
B．are
C．has been
D．have been
答案
更多“Trial and error ______ the source of our knowledge.A．isB．areC．has beenD．have been”相关的问题
第1题
According to the passage, an oath was declared "burst" during compurgation if the ______.
A．swearer made an error in the exact form. of the required ritual
B．swearer could not round up the required number of oath-helpers
C．swearer preferred trial by ordeal, or by battle
D．judges decided that the oath was false or unnecessary
第2题
Which of the following statements is not true of a trial balance？______.
A．A trial balance is a list of balances of ledger accounts worked out periodically.
B．A trial balance can detect an omission in the recording of the accounting data.
C．A trial balance provides an accuracy check by showing whether or not total debits equal total credits.
D．If total debits do not equal total credits in a trial balance, accounting error has occurred somewhere in journalizing or posting.
第3题
A.an error in determining the account balances, such as a balance being incorrectly computed
B.recording the same transaction more than once
C.failure to record a transaction
D.recording the same erroneous amount for both the debit and the credit parts of a transaction
第4题
As hard as【C5】______may be, sit back and chill, experts advise. Though you've got to get them to do it,【C6】______helping too much, or even examining【C7】______too carefully, you may keep them【C8】______doing it by themselves. "I wouldn't advise a parent to check every【C9】______assignment," says psychologist John Rosemond, author of Ending the Tough Homework. There's a【C10】______of appreciation for trial and error, let your children【C11】______the grade they deserve.
Many experts believe parents should gently look over the work of younger children and ask them to rethink their【C12】______. But "you don't want them to feel it has to be【C13】______." she says. That's not to say parents should【C14】______homework first, they should monitor how much homework their kids【C15】______. "Thirty minutes a day in the early elementary years and an hour in【C16】______four, five, and six is standard, "says Rosemond ,"For junior-high students it should be【C17】______more than a hour and a half, and two for high school students. "If your child【C18】______has more homework than this. You may want to check【C19】______other parents and then talk to the teacher about【C20】______assignments.
【C1】
A．very
B．exact
C．right
D．schools
第5题
Her search for natural movement form. sent her to nature. She believed movement should be as natural as the swaying of the trees and the rolling waves of the sea, and should be in harmony with the movements of the Earth. Her great contributions are in three areas.
First, she began the expansion of the kinds of movements that could be used in dance. Before Duncan danced, ballet was the only type of dance performed in concert. In the ballet the feet and legs were emphasized, with virtuosity shown by complicated movements. Duncan performed dance by using all her body in the freest possible way. Her dance stemmed from her soul and spirit. She was one of the pioneers who broke tradition so others might be able to develop the art.
Her second contribution lies in dance costume. She discarded ballet shoes and stiff costumes. These were replaced with bare feet, and unbound hair. She believed in the natural body being allowed to move freely, and her dress displayed this ideal.
Her third contribution was in the use of music. In her performances she used the symphonies of great masters, including Beethoven and Wagner, which was not the usual custom.
She was as exciting and eccentric in her personal life as in her dance.
According to the passage, what did nature represent to Isadora Duncan？
A．Something to conquer.
B．A model for movement.
C．A place to find peace.
D．A symbol of disorder.
第6题
Winged Robot Learns to Fly
Learning how to fly took nature millions of years of trial and error --but a winged robot has cracked it in only a few hours, using the same evolutionary principles.
Krister Wolff and Peter Nordin of Chalmers University of Technology (CUT) in Gothenburg, Sweden, built a winged robot and set about testing whether it could learn to fly by itself, without any pre-programmed data on what flapping is or how to do it.
To begin with, the robot just twitched and jerked erratically. But, gradually, it made movements that gained height. At first, it cheated -- simply standing on its wing tips was one early short cut. After three hours, however, the robot abandoned such methods in favor of a more effective flapping technique, where it rotated its wings through 90 degrees and raised them before twisting them back to the horizontal and pushing down.
"This tells us that this kind of evolution is capable of coming up with flying motion," says Peter Bentley, who works on evolutionary computing at University College London. But while the robot had worked out how best to produce lift, it was not about to take off. "There's only so much that evolution can do," Bentley says. "This thing is never going to fly because the motors will never have the strength to do it," he says.
The robot had metre-long wings made from balsa wood and covered with a light plastic film. Small motors on the robot let it move its wings forwards or backwards, up or down or twist them in either direction.
The team attached the robot to two vertical rods, so it could slide up and down. At the start of a test, the robot was suspended by an elastic band. A movement detector measured how much lift, if any, the robot produced for any given movement. A computer program fed the robot random instructions, at the rate of 20 per second, to test its flapping abilities. Each instruction told the robot either to do nothing or to move the wings slightly in the various directions.
Feedback from the movement detector let the program work out which sets of instructions were best at producing lift. The most successful ones were paired up and "offspring" sets of instructions were generated by swapping instructions randomly between successful pairs. These next-generation instructions were then sent to the robot and evaluated before breeding a new generation, and the process was repeated.
Which of the following is NOT true of what is mentioned about the winged robot in the second paragraph？
A．The two professors of CUT built the winged robot.
B．The two professors of CUT tested whether the winged robot could learn to fly.
C．The two professors of CUT programmed the data on how the robot flapped its wings.
D．The two professors of CUT tried to find out if the robot could fly by itself.
第8题
The author watched the Watergate trial carefully on the TV.
A．Y
B．N
C．NG
第9题
A．different trial court in the same state
B．court in a different geographic region
C．federal trial court
D．state supreme court
第10题
There is a simultaneous trial taking place in the next building.
A.fair
B.full
C.coexisting
D.public
