夏、商、西周是我国奴隶社会的形成发展时期。小明对这一时期的国都和建立者很感兴趣，现请你帮其完成下列表格：

朝代	建立者	都城
夏	禹之子	____
商	____	毫
西周	周武王	____

将灵敏电流计G串联一个电阻R，此组合可以用来测电压．现将该组合与一标准电压表并联，如图所示，对某一电路进行测量，发现测出的电压总比标准电压表测出的值略微偏小．为了使其读数准确，应在串联电阻R上再 （　　）

已知A，B是两个锐角，且满足 ${\sin }^{2}A+{\cos }^{2}B=\frac{5}{4}t$ ， ${\cos }^{2}A+{\sin }^{2}B=\frac{3}{4}{t}^2$ ，则实数t所有可能值的和为（   ）

阅读理解

    Why Do People Blink Their Eyes?

    People blink(眨眼) their eyes tens of thousands of times every day. Scientists have long believed blinking was an involuntary movement and served mainly to keep the eyeballs wet. But a new study suggests it has a more important purpose.

    An international team of scientists from the University of California at Berkeley studied the blinking of human eyelids. The journal Current Biology published their findings. The team said they found that blinking “repositions our eyeballs so we can stay focused” on what we are seeing. They said that when we blink our eyelids, the eyes roll back into their sockets--the bony area that surrounds and protects the eyes. However, the researchers found the eyes don't always return to the same position. They said this causes the brain to tell the eye muscles to reorganize our eyesight.

    Gerrit Maus is the lead writer of the report. He serves as an assistant professor of psychology at Nanyang Technological University in Singapore. Maus says: “Our eye muscles are quite sluggish(迟缓的) and imprecise, so the brain needs to constantly adapt its motor signals to make sure our eyes are pointing where they're supposed to. Our findings suggested that the brain measures the difference in what we see before and after a blink, and commands the eye muscles to make the needed corrections.” The researchers said that without such corrections our surroundings would appear unclear and even jumpy. They said the movement acts “like a Steadicam(摄影稳定器) of the mind.”

    The researchers said they asked volunteers to sit in a dark room while staring at a small dot on a flat surface. They used special cameras to follow the volunteer's blinks and eye movements. After each blink, the dot was moved one centimeter to the right. The volunteers did not notice this, but the brain did. It followed the movement and directed the eye muscles to refocus on the dot. After the dot was moved in this way 30 times, the volunteers' eyes changed their focus to the place where they predicted it would be.

    Professor Maus says “Even though participants did not consciously register that the dot had moved, their brains did, and adjusted with the corrective eye movement. These findings add to our understanding of how the brain constantly adapts to changes, commanding our eye muscles to correct for errors in our bodies' own hardware.”

有3张边长为a的正方形纸片，4张边长分别为a、b（b＞a）的矩形纸片，5张边长为b的正方形纸片，从其中取出若干张纸片，每种纸片至少取一张，把取出的这些纸片拼成一个正方形（按原纸张进行无空隙、无重叠拼接），则拼成的正方形的边长最长可以为(   )