单选题下列哪些说法是正确的？（）①图像都是由像素组成的，通常称位图或点阵图②图形也称矢量图，矢量图放大若干倍后，还是清晰无失真③图像的最大优点是容易进行移动、缩放、旋转和扭曲等变换A①②③B②③C①②D①③
单选题
下列哪些说法是正确的？（）①图像都是由像素组成的，通常称位图或点阵图②图形也称矢量图，矢量图放大若干倍后，还是清晰无失真③图像的最大优点是容易进行移动、缩放、旋转和扭曲等变换
A
①②③
B
②③
C
①②
D
①③
参考解析
解析：
③是矢量图的特点。
相关考题：
单选题Which of the following activities is most likely interactive? _____AMimickingBRole playCProblem solvingDPlay game
单选题A t=0.10s时，质点P的速度方向向下B t=0.10s时，质点P的加速度大于质点O的加速度C 从t=0.10s到t=0.25s，质点P运动的路程为30cmD 若这列波的波源正在远离观察者，则观察者接收到的频率大于波源发出的频率
单选题“Auld Lang Syne”was written by the author of _____.AA Red, Red RoseBThe Sick RoseCA Rose for EmilyDTiger
单选题Passage 2As regards social conventions，we must say a word about the wel-known English class system. This is an embarassing subject for English people，and one they tend to be ashamed of，though during the present century class-consciousness has grown less and less，and the class system less rigid. But it still exists below the surface. Broadly speaking，it means there are two clases，themiddle classand theworking class”.（We shall ignore for a moment the old“upper class，including the hereditary aristocracy，since it is extremely small in numbers；but some of its members have the right to sit in the House of Lords，and some newspapers take surprising interest in their private life.）The middle class consists chiefly of well-to-do businessmen and professional people of all kinds. The working class consists chiefly of manual and unskilled workers.The most obvious difference between them is in their accent. Middle-class people use slightly varying kinds ofreceived pronunciationwhich is the kind of English spoken by BBC announcers and taught to overseas pupils. Typical working-class people speak in many different local accents which are generally felt to be rather ugly and uneducated. One of the biggest barriers of social equality in England is the two-class education system. To have been to a so-called public schoolimmediately marks you out as one of the middle class. The middle classes tend to live a more formal life than working-class people, and are usually more cultured. Their midday meal is lunchand they have a rather formal evening meal called dinner, whereas the working man's dinner, if his working hours permit, is at midday, and his smaller, late-evening meal is called supper.As we have said, however, the class system is much less rigid than it was, and for a long time it has been government policy to reduce class distinctions. Working-class students very commonly receive a university education and enter the professions, and working-class incomes have grown so much recently that the distinctions between the two classes are becoming less and less clear. However, regardless of one's social status, certain standards of politeness are expected of everybody, and a well-bred person is polite to everyone he meets, and treats a laborer with the same respect he gives an important businessman. Servility inspires both embarrassment and dislike. Even the wordsir, except in school and in certain occupations(e.g. commerce, the army, etc.) sounds too servile to be commonly used.The most obvious difference between the working class and the middle class in English is their_______.AdressBworkCaccentDmeal
单选题Passage 1Every day 25 million U.S. children ride school buses. The safety record for these buses is much better than for passenger cars; but nevertheless, about 10 children are killed each year riding on large school buses, and nearly four times that number are killed outside buses in the loading zones. By and large, however, the nation's school children are transported to and from school safety.Even though the number of school bus casualties is not large, the safety of children is always of intense public concern. While everyone wants to see children transported safely, people are divided about what needs to be done particularly whether seat belts should be mandatory.Proponents of seat belts on school buses-many of them parents and medical organizations argue that seat belts are necessary not only to reduce fatality and injury, but also to teach children lessons about the importance of using them routinely in any moving vehicle. A side benefit, they point out, is those seats belts help keep children in their seats, away from the bus driver.Opponents of seat belt installation suggest that children are already well protected by the school buses that adhere to the Nation Highway Traffic Safety Administrations(NHTSA) safety requirements set in 1977. They also believe that many children won't wear seat belts anyway and that may damage the belts or use them as weapons to hurt other children.A new Research Council report on school bus safety suggests that there are alternate safety devices and procedures that may be more effective and less expensive. For example, the study committee suggested that raising seat backs four inches may have the same safety effectiveness as seat belts.The report sponsored by the Department of Transportation at the request of Congress, reviews seat belts extensively while taking a broader look at safety in and around school buses.It may be inferred from this passage that_________.Amany of the opponents of seat belt installation are parents and officials of the Department of TransportationBproposals of seat belts on school buses would be seriously consideredCan alternate safety device raising seat backs four inches may be taken into considerationDThe Department of Transportation may either take the idea of seat belts or other measures when it reviews the whole situation
单选题义务教育音乐课程内容的四个领域是（）。A感受与鉴赏、表现、创造、音乐与相关文化B感受与欣赏、表现、创造、音乐与相关文化C感受与欣赏、表现、创作、音乐与相关文化D感受与鉴赏、表演、创造、音乐与相关文化
单选题What is the teacher doing by saying this in terms of instruction?“Now， did the questions help you understand the text better?”AObserving the activity.BEvaluating the actMty.CMonitoring the activity.DControlling the activity.
单选题A 氢原子从n=2跃迁到n=1的能级时，辐射光的波长大于656nmB 用波长为325nm的光照射，可使氢原子从n=1跃迁到n=2能级C 一群处于n=3能级上的氢原子向低能级跃迁时最多产生两种谱线D 用波长为633nm的光照射时，不能使氢原子从n=2跃迁到n=3能级
单选题A 玻璃中a光的传播速度比b光的大B 玻璃对口光的折射率比对b光的大C 在相同条件下做双缝干涉，a光产生的条纹间距比b光窄D 将a、b光以相同的入射角从玻璃射向空气，若b光能发生全反射，则a光也一定能发生全反射
填空题岩鸽蛋一端大，一端小，受到触动时多打转，少滚动，减少了摔破的危险，这对于它在悬岩上产卵是有利的，这种现象是（）的结果，如果卵是圆形的，则在（）中被淘汰。说明自然选择是定向的，它是通过（）来实现的。
问答题案例：下面是在完成“探究摩擦力的大小与什么因素有关”的实验后，教师对实验进行改进的教学片段：教师：对摩擦力现象，同学们已经有了丰富的感性认识。经过此节实验课，同学们也知道了摩擦力与什么因素有关。这次实验中还存在哪些不足呢？学生：实验过程中，弹簧测力计的示数不稳定。教师：对，这是需要改进的地方。学生：接触面光滑程度不一样，能不能改进？教师：根本就没有粗糙程度一样的木板。我们可以把弹簧测力计的一端固定，另一端与木块固定相连，将它们放置在长木板上，拉动长木板，观察弹簧测力计的示数，这样可以有效减小弹簧晃动带来的误差。经过教师的改进，学生们重新设计了实验，并得到更接近真实值的结果。问题：(1)对上述课堂实录进行评析。（15分）(2)请设计一个新的教学片段，以改进上述问题。（15分）