下列关于免疫的叙述正确的是（   ）
① 淋巴细胞只有受到抗原刺激后，才能形成效应细胞和记忆细胞
② 一种抗原不仅可以和相应的抗体结合，也可以与产生抗体的效应细胞结合
③ 在特异性免疫发挥作用的主要是淋巴细胞
④ 当机体免疫功能不足或缺乏时，可引起免疫缺陷病
⑤ 浆细胞的产生，需要T细胞和抗原的共同刺激
⑥ 在体液免疫过程中，每个浆细胞只分泌一种特异性抗体
⑦ 当同一种抗原再次进入机体时，产生的浆细胞均来自记忆细胞

下列词语不是关于中东的有（　　）

如图的各组图形中，相似的是（　　）

      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!

两组数据3，a，2b，5与a，6，b的平均数都是8，若将这两组数据合并为一组数据，则这组新数据的众数为____，中位数为____．