单选题向刚切开的马铃薯表面滴几滴碘水。其表面立即显蓝色，说明马铃薯中含有______。 A.维生素 B.淀粉 C.蛋白质 D.纤维素

单选题《水浒传》中《林教头风雪山神庙》一章中“仍旧迎着朔风回来”的“朔”是指方位中的（　　）。

单选题儿童离开了玩具就不会游戏，说明其思维方式是()。

单选题男性运动员长期服用类固醇类兴奋剂，可能的危害是( )。

单选题下列晶体模型对应的物质熔化时破坏共价键的是()。

单选题One evening, while Marcos Ugarte was doing his homework and his father, Eduardo, prepared lesson plans, they heard someone yelling outside. Eduardo, 47, and Marcos, 15, stepped onto the porch of their home in Troutdale, Oregon, and saw a commotion four doors down, outside the home of their neighbors, the Ma family. "I didn't think anything was wrong," Eduardo recalls. "I told Marcos we should give them some privacy." He headed back inside, but Marcos's eye was caught by a glow from the Ma house. "Dad, the house is on fire! " Marcos cried. Clad only in shorts, the barefoot teen sprinted toward the Ma's home with his dad. Grandmother Yim Ma, mother Suzanne Ma, and son Nathan Ma were gathered on the front lawn yelling for help. When the Ugartes got there, they saw father Alex Ma stumbling down the stairs, coughing, his face black with soot. "Is anyone else in the house?" Eduardo asked. "My son! " Alex managed to say, pointing to the second floor. Eduardo started up the stairs, but thick, black smoke, swirling ash, and intense heat forced him to his knees. He crawled upstairs and down the hall where Alex said he would find Cody, eight, who had locked himself in a bedroom. As the fire raged across the hall, Eduardo banged on the bedroom door and tried to turn the doorknob. Cody didn' t respond. Eduardo made his way back downstairs. Meanwhile, Marcos saw Yim and Suzanne pulling an aluminum ladder out of the garage. "Cody was standing at the window, screaming for help," says Marcos. "I knew I had to do something." He grabbed the ladder, positioned it near the window, and climbed toward the boy. When Marcos reached the window, he pushed the screen into the room and coaxed Cody out. "It's OK," Marcos told him. "I've got you." Holding Cody with one arm, Marcos descended the ladder. When firefighters arrived, plumes of black smoke were billowing from the back of the house as flames engulfed the second floor. Emergency personnel took Cody to a nearby hospital, where he was treated for smoke inhalation and released. No one else was injured. The cause of the blaze is still under investigation. "You just don't see a teenager have that kind of composure ," says Mark Maunder, Gresham Fire Department battalion chief. The Ma family relocated. The day after the fire, Alex visited Marcos. "Thank you for saving my son. Alex said. "You are his hero forever."

单选题师生在教育内容的教学上应该是(　　)。

单选题某中学政治老师在课上为了让学生更加深入地了解“量变引起质变”的道理，将班上的同学分组进行讨论，结合教师教学的相关知识，这位教师该怎样分组?（　）

单选题下列作品与其作者对应正确的是______。 A.《拇指姑娘》——霍夫曼 B.《爱丽丝漫游奇境记》——查尔斯·路德维希·道奇森 C.《雾都孤儿》——契诃夫 D.《汤姆叔叔的小屋》——马克·吐温

单选题如图所示，一条电场线与Ox轴重合，取O点电势为零，Ox方向上各点的电势φ随x变化情况如图所示，若在O点由静止释放一电子，电子仅受电场力作用，则判断正确的是()。

单选题某算法的流程图如下所示，当输入a、b的值分别为7、9，该算法的输出结果为()。

单选题儿童认知能力中，最先发展且速度最快的领域是()。

单选题让脸上抹有红点的婴儿站在镜子前，观察其行为表现，这个实验测试的是婴儿哪方面的发展?()

单选题1907年蒙台梭利在罗马贫民区创办的、采用一些特殊方法训练处境不利的贫穷儿童的教育机构名称是()。

单选题在师生沟通过程中，不能起到含蓄作用的是()。

单选题“高原现象”通常发生在技能学习过程中的哪个阶段?______。 A.初期 B.中期 C.后期 D.各阶段都可能

单选题小学《科学》课程整合了自认科学各学科的内容，这种课程属于（　　）

单选题下面选项是对信息的实质的理解和说明，其中错误的选项是______。 A.信息就是计算机的处理对象 B.信息就是关于事物运动的状态和规律的知识 C.信息就是信息，既不是物质，也不是能量 D.信息就是人类同外部世界进行交换的内容的名称

单选题在中国，______提出了“不愤不启，不悱不发”的著名教学原则。 A.孟子 B.孔子 C.荀子 D.庄子

单选题美术演示教学的目的是( )。