单选题已知球的半径为2，相互垂直的两个平面分别截球面得两个圆，若两圆的公共弦长为2则两圆的圆心距等于｛ ｝．

单选题已知a=mi+j-2k，b=-3i+j-nk是空间中的两个向量，则“a⊥bb”是“m=1，n=1”的______．

单选题若想在Word的编辑状态下进行粘贴操作。可以单击常用工具栏中（ ）按钮

单选题《中华人民共和国义务教育法》规定，儿童入学年龄的标准是______。

单选题叶绿体是植物进行光合作用的场所。下列关于叶绿体结构与功能的叙述，正确的是______。

单选题结核杆菌是结核病的病原体。近年来因抗药菌株增多等原因，使人类结核病的发病率和死亡率上升。下列有关结核杆菌的叙述，正确的是( )。

单选题陶行知说：“你的教鞭下有瓦特，你的冷眼中有牛顿，你的讥笑中有爱迪生。”与之相关联的教师职业道德是______

单选题Three years ago I listened to a lecture on cognition (认知) that changed the way I think about intelligence. There are two types of cognition. The first is normal cognition: the ability to regain knowledge from memory. The second type of cognition is metacognition: the ability to know whether or not you know. Does this affect intelligent? In traditional education, intelligence is measured by cognitive ability. Some people can easily produce everything they know on a test. But others are awarded with poor grades and considered inferior. But does this inability make them any less intelligent? If the question came up on a task, they could refer to a book or a quick Google search. In reality they"re just as effective as the people that ace a test. They just can"t prove it as easily. Metacognition is more important to success than cognition. A person with poor cognitive ability, but great metacognition ability might do poorly in school, but when faced with a challenge, they understand their abilities and take the best course of action . For example, when face with a question, a person with strong metacognition ability will deal with it like this. If he knows the answer, but can"t come up with it, he can always do a bit of research. If he knows for sure that he doesn"t know, then he can start educating himself. Because he"s aware of his ignorance, he doesn"t act with foolish confidence. These people might not seem intelligent at first glance, but because they know what they know, they make better decisions and learn the most important things. However, people with great cognitive ability but poor metacognition ability may be considered excellent at a young age for acing every test and getting great SAT scores. Unfortunately, they"ve been ruined by poor metacognition: they think they know everything but they really don"t. They are overconfident, fail to learn from mistakes, and don"t understand the slight differences of personal relationships, showing disregard for persons with lower cognitive ability. They may make the worst decisions. The most important mental power is the ability to know what you don"t know. The recognition of a fault is the first step to improvement. Don"t try to hide a lack of knowledge. For intelligent people this is the toughest lesson to learn.

单选题下面对文学常识的表述，不正确的是______。

单选题俄罗斯作曲家柴可夫斯基一生不但创作了许多著名的交响乐曲，而且还创作了三部经典舞剧。它们分别是______

单选题对于外部世界的一点一滴，婴儿已经在头脑中建立起了某种“模型”，形成了对外部世界的某种看法。如果这种模型与外部世界相符合，他们就感到满意；如果不符合，即所期望的结果没有出现，他们就感到不满意。 根据这段话的意思，假如一个婴儿对着他所熟悉的面孔微笑，则说明（　　）。

单选题教师负有维持课堂教学秩序和教学纪律的责任，这属于教师的( )角色。

单选题体操技巧练习中，头手倒立正确的着垫部位是( )。

单选题在思维过程中，从看似相似或相似的事物中寻找其不同点的比较，属于下列哪种比较形式？（ ）

单选题不属于影响阅读教学的因素的一项是______。 A.智力水平 B.生理条件 C.社会经济文化背景 D.教师年龄

单选题关于下图所示装置的用途，说法正确的是______。

单选题下列对美术课程评价目的的表述，错误的是______

单选题已知二氯化二硫(S2Cl2)的结构式为Cl—S—S—Cl，它易与水反应：4HCl+SO2↑+3S↓，对该反应的说法正确的是______A．S2Cl2既作氧化剂又作还原剂B．H2O作还原剂C．每生成1molSO2转移4mol电子D．氧化产物与还原产物物质的量比为3:1

单选题1700—1830年间，广州白银流入的净数约1亿英镑，其中绝大部分来自英国。这一时期英国对华贸易主要是( )。

单选题下列属于情绪外部表现的一项是( )