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设\(f(x)=sin\ x\)，则\(f^{(50)}(x)=\)\(-sin\ x\)________.
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UFOs
Sixty years ago, a man named Kenneth Arnold saw something that we can still __________ (51)today-- something that changed popular culture for ever.
Flying his plane over mountains in the US state of Washington, he saw a line of strange objects, either crescent-shaped (月牙形的 ) or disc-like, flying __________ (52) the motion of a saucer (碟) skimming (飞速掠过) on water.
The media soon picked up on the story--the Flying Saucers were here! Was the earth being__________ (53) by creatures from another planet？ Soon, So many sightings were made that the US military began to __________ (54). It called these strange Objects UFOs--Unidentified Flying Objects, and that is how they are __________ (55)today.
Military investigations found no evidence of visitors from outer space. But that did not stop the true __________ (56). The military were __________ (57) up, they said. Or maybe it was because the travelers from space were of such superior intelligence __________ (58) they could hide from military analysts (分析家) .
People have always seen strange lights in the sky. In the past these were explained in __________ (59)ways. In a world where religion was less infuenfial and science fiction was popular, signs from God were replaced by visitors from other __________ (60).
The date of the first UFO sightings was also significant. In 1947, World War I! had just ended and the __________ (61) War was just beginning. Humanity seemed locked in endless conflicts.
Like generations before them, people looked __________ (62) the skies for help. But instead of seeking God, they looked for help from super-intelligent aliens (外星人) with __________ (63)technology. Belief in UFOs became the first religion of science.
However, even people who believe in UFOs are not quite sure why they visit the earth. The universe is a big place and it is __________ (64) to assume that there is life somewhere out there.
It is possible that aliens have worked out how to travel through space. Yet some people report that they have been taken by aliens and have had experiments __________ (65) on them. Why would anyone travel across half the universe to conduct medical experiments on people living in small towns in the United States？
___________ 查看材料
Many a young person tells me he wants to be a writer. I always encourage such people, but I also explain that there’s a big difference between "being a writer" and writing. In most cases these individuals are dreaming of wealth and fame, not the long hour alone at a typewriter. "You’ve got to want to write," I say to them, "not want to be a writer. "
The reality is that writing is a lonely, private and poor paying affair. For every writer kissed by fortune there are thousands more whose longing is never rewarded. When I left a 20 year career in the U. S. Coast Guard to become a freelance (自由栏目) writer, I had no prospects at all. What I did have was a friend who found me my room in a New York apartment building. It didn’t even matter that it was cold and had no bathroom. I immediately bought a used manual typewriter and felt like a genuine writer.
After a year or so, however, I still hadn’t gotten a break and began to doubt myself. It was so hard to sell a story that I barely made enough to eat. But I knew I wanted to write, I had dreamed about it for years. I wasn’t going to be one of those people who die wondering: What if？ I would keep putting my dream to the test even though it meant living with uncertainty and fear of failure. This is the shadow land of hope, and anyone with a dream must learn to live there.
The passage is meant to__________ 查看材料
第三组：Following a security incident, in which the response measures outlined in the Ship Security Plan (SSP) have been activated, there will be a thorough review of their effectiveness and details will be made available, on request, to persons duly authorized by the Ship&39;s Flag State Administration. The Ship Security Plan is not subject to detailed inspection (other than confirming its existence on the ship) by duly authorized officials of a port State unless there are "clear grounds" to believe that the ship is not in compliance with the requirements of SOLAS or the ISPS Code, and the only means to verify or rectify the non-compliance is to review the relevant sections of the Plan. In such cases, access to the Restricted parts of the Plan relating to the non-compliance is exceptionally allowed, but only with the consent of the Flag State, or the master. If the master, in his professional judgment, believes that such "clear grounds" exist, and allowing access to relevant sections of the Restricted part of the Plan might resolve the situation, such access can be exceptionally granted. However, this should be immediately reported by the ship to the Company Security Officer (CSO). If access to the Restricted part of the Plan is denied by the master, this should be immediately reported by the ship to the Company Security Officer for guidance and reference to the Flag State.
The Confidential part of a SSP cannot be subject to non-flag State inspection unless otherwise agreed by the contracting governments concerned. Any such request or demand by port state officials to view sections of the Confidential part of the Plan will be immediately reported by the ship to the Company Security Officer for guidance and reference to the flag State before any details are revealed to non-flag State officials. The Confidential provisions, which from an integral part of this Plan, are held by the Ship Security Officer (SSO)
After a security incident, the revision of the SSP will made by____.
阅读以下说明和 C 代码，填补代码中的空缺，将解答填入答题纸的对应栏内。 【说明】 对一个整数序列进行快速排序的方法是：在待排序的整数序列中取第一个数作为基准值，然后根据基准值进行划分，从而将待排序列划分为不大于基准值者(称为左子序列)和大于基准值者(称为右子序列)，然后再对左子序列和右子序列分别进行快速排序， 最终得到非递减的有序序列。 函数 quicksort(int a[]，int n)实现了快速排序，其中，n 个整数构成的待排序列保存在数组元素 a[0]-a[n-1]中。
【C 代码】 include ＜ stdio.h＞ void quicksort(int a[] ，int n) { int i ，j; int pivot = a[0]; //设置基准值 i =0; j = n-l; while (i＜ j) { while (i1) （3） ; //递归地对左子序列进行快速排序 if (n-i-1＞1 ) （4） ; //递归地对右子序列进行快速排序 } int main () { int i，arr[ ] = {23，56，9，75，18，42，11，67}; quicksort (（5） ); //调用 quicksort 对数组 arr[ ]进行排序 for(i=0; i
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