题目

若α的终边过点P(2sin30°，－2cos30°)，则sinα的值为( ) A.                                                             B．－ C．－                                                     D．－ 答案：C [解析] P(2sin30°，－2cos30°)即P(1，－)， ∴r＝2，故sinα＝－，故选C.One day in winter, a couple of good friends headed for a frozen lake nearby to skate on ice. The boys were between five and ten years old. When they were skating, one of the boys headed deeper into the lake, but _____ he found himself skating on very _____ ice. Before he could _____ it, he had fallen through the ice into the icy water below. Having seen this, his friends _____ towards him but could not get him out of the lake _____ the ice layer had formed back and the boy was _____ under the transparent layer. They could see him _____ but could do nothing to help him. Then one of his friends _____ to see a tree in the distance. He skated to it as fast as he could, _____ a branch and then with all his ______ he started digging into the ice. His work proved ______ and he managed to make a hole ______enough to pull his friend out.By the time the ambulance arrived, a small crowd had gathered. They were all ______ the rescuer for his ______and calmness. However, they were all surprised as well, and ______ how a young boy could break such a big branch. ______， the branch was bigger and heavier than what a person of that age group could carry, drag it to the spot and ______ it again and again to hammer a hole in the ice. It looked like a superhuman ______. How? How did he manage to do it? It was impossible! During the ______， an old man spoke up, “I know how he did it.” Everybody looked at him in ______. The old man said, “He could do it because there was nobody around him who said he couldn't！”1.A. unfortunately B. probably C. unfairly D. hardly2.A. cold B. heavy C. light D. thin3.A. stand B. realize C. clear D. protect4.A. shouted B. laughed C. rushed D. waved5.A. because B. though C. if D. unless6.A. sent B. pushed C. trapped D. seated7.A. shaking B. struggling C. trying D. breathing8.A. seemed B. continued C. wanted D. happened9.A. borrowed B. touched C. broke D. climbed10.A. strength B. wealth C. interest D. freedom11.A. true B. successful C. attractive D. risky12.A. bright B. deep C. large D. round13.A. praising B. comforting C. encouraging D. advising14.A. honesty B. bravery C. generosity D. knowledge15.A. imagined B. replied C. imitated D. wondered16.A. Obviously B. Hopefully C. Delightfully D. Occasionally17.A. throw B. raise C. turn D. knock18.A. sign B. lesson C. effort D. idea19.A. performance B. break C. meeting D. discussion20.A. advance B. silence C. despair D. belief