人类在探索自然规律的过程中，总结出了很多科学探究方法．下列实验探究采用了“理想模型法”的是

（   ）

【20世纪的战争与和平】阅读下列材料，回答问题。

材料：历史上，中国虽然宣布了参加第一次世界大战，但并没有真正派出军队参战。真正卷入战争的中国人，是14万中国劳工，协约国称为“中国劳工旅”。

    在欧洲战场上，以英法为首的协约国在德国的步步紧逼下损失惨重，面临着严重的人力资源危机。……为了更多的欧洲人从工业劳动中解放出来走向前线参战，英国和法国将他们的目光投向中国廉价又丰富的人力资源。……1916年至1918年间，英法两国在中国共招募华工14万人左右。按照最初约定，华工的工作是以工代兵，并不参战，但事实上华工的工作几乎都是处于最前线。他们到欧洲后多从事挖掘战壕、筑路、救护伤员等战勤和战斗工作，约两万人付出了自己的生命，有的只有工号连名字都没有留下。

中国劳工旅的大多数人在1919年和1920年回国，留下来的三千人在欧洲扎下了根，构成了当时法国和比利时华人社会的核心。

    李肇星在凭吊一战赴欧华工墓地后表示，许多一战华工战后成为第一批移居法国的华人，为中法友谊做出贡献。

——摘编自光明网《14万中国劳工参加一战》

化石是研究生物进化的唯一证据．（判断对错）

现定义运算“★”，对于任意实数a、b，都有a★b=a²-3a+b，如：4★5=4²-3×4+5，若x★2=6，则实数x的值是（　　）

      Computers can help many workers. They can also help thieves.
      There was one thief who worked in a bank of the United States. He paid for everything he needed by check (支票). Then he told the computer not to take any money from his account for the checks he wrote. The bank's computer did what he said. And it did not take any money from his bank account. One day the computer broke down. People had to do the computer's work. They soon found out what was happening.
      Another thief, who worked for a bank saw people filling in deposit forms (存款单). Many of these people did not know their account numbers, so they wrote only their names on the forms. They left empty places for their account numbers. The thief wrote his own account number in this place. When the computer read these forms it looked only at the account numbers. It did not look at the customers' names. It paid the money on these deposit forms into the thief's account .                           
       Then there was the bank worker who told the bank computer to take ten cents off every customer's account each month and put it into his own account. For a long time the bank's customers did not notice that they were losing ten cents every month. But then someone did notice and told the bank. That was the end of that little game!