单选题：There are 20 blanks in the following passage. For each blank

There are 20 blanks in the following passage. For each blank there are four choices marked A）, B）, C） and D） on the right side of the paper. You should choose the ONE that best fits into the passage. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.Passage TwoQuestions are based on the following passage.　　In 1915 Einstein made a trip to G ttingen to give some lectures at the invitation of the mathematical physicist David Hilbert. He was particularly eager—too eager, it would turn （62）—to explain all the intricacies of relativity to him. The visit was a triumph, and he said to a friend excitedly, “I was able to （63） Hilbert of the general theory of relativity. ” （64） all of Einstein’s personal turmoil（焦躁）at the time, a new scientific anxiety was about to （65）. He was struggling to find the right equations that would （66） his new concept of gravity, （67） that would define how objects move （68） space and how space is curved by objects. By the end of the summer, he （69） the mathematical approach he had been （70） for almost three years was flawed. And now there was a （71） pressure. Einstein discovered to his （72） that Hilbert had taken what he had learned from Einstein’s lectures and was racing to come up （73） the correct equations first.
　　It was an enormously complex task. Although Einstein was the better physicist, Hilbert was the better mathematician. So in October 1915 Einstein （74） himself into a month-long frantic endeavor in （75） he returned to an earlier mathematical strategy and wrestled with equations, proofs, corrections and updates that he （76） to give as lectures to Berlin’s Prussian Academy of Sciences on four （77） Thursdays.
　　His first lecture was delivered on Nov. 4. 1915, and it explained his new approach, （78） he admitted he did not yet have the precise mathematical formulation of it. Einstein also took time off from （79） revising his equations to engage in an awkward fandango （方丹戈双人舞）with his competitor Hilbert. Worried （80） being scooped（抢先），he sent Hilbert a copy of his Nov. 4 lecture. “I am （81） to know whether you will take kindly to this new solution, ”Einstein noted with a touch of defensiveness. A．up
B．over
C．out
D．off