2016年12月28日，我国东西向里程最长的高铁线——沪昆线全线通车，从上海到昆明只要10小时，实现了“朝辞上海，暮至昆明”。右图为沪昆高铁示意图。读图，完成下题。

（2009白银市）计算：（　　）

Be（OH）₂是两性的，跟强酸反应时生成Be²⁺，跟强碱反应时生成BeO₂^2﹣．现有三份等物质的量浓度、等体积的BeCl₂、MgCl₂、AlCl₃溶液（配制时均加入少量盐酸），现将一定浓度的NaOH溶液分别滴入三种溶液中至过量，NaOH溶液的体积x（mL）与生成沉淀的物质的量y（mol）的关系如图所示，则与BeCl₂、MgCl₂、AlCl₃三种溶液对应的图象正确的是（　　）

阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

    Charlie Chaplin was considered to be one of the most popular ____ (star) in the early days of films. He brightened the lives of people throughout the world ____(use) his perfect acting. Charlie was born in a poor family and lived ____ hard life in his childhood. His parents were both poor hall performers,____ didn't make much money. Therefore, at a very young age, Charlie had to learn ____ (sing) and dance. By his teens, his subtle acting had become so entertaining ____ no one in England was ever bored watching him mime and act the fool doing ordinary everyday tasks. In 1972, he won a special Oscar ____his outstanding work in the films that he wrote, directed, produced, and starred in. He made people laugh even when they felt depressed. And no one has done ____ (well) than him up to now.

    Charlie lived in England and the USA but ____(spend) his last years in Switzerland, where he died of ____ (nature) causes on December 25, 1977.

如图所示电路中，A，B为两个金属夹，分别在两金属夹之间接入硬币、铅笔芯、橡皮或塑料尺，闭合开关后观察小灯泡是否发光．在观察到小灯泡发光时，两金属夹之间接入的可能是（   ）