问题
单项选择题
以下关于机器语言的描述中，不正确的是( )。
A．每种型号的计算机都有自己的指令系统，就是机器语言
B．机器语言是惟一能被计算机识别的语言
C．计算机语言可读性强，容易记忆
D．机器语言和其他语言相比，执行效率高
答案
参考答案：C
解析：机器语言中每条指令都是一串二进制代码，因此可读性 差，不容易记忆，编写程序复杂，容易出错。
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以下关于机器语言的描述中，不正确的是( )。
A．每种型号的计算机都有自己的指令系统，就是机器语言
B．机器语言是惟一能被计算机识别的语言
C．计算机语言可读性强，容易记忆
D．机器语言和其他语言相比，执行效率高
参考答案：C
解析：机器语言中每条指令都是一串二进制代码，因此可读性 差，不容易记忆，编写程序复杂，容易出错。
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| Mrs Black was a famous musician several years ago. She taught 1 at a school and her students did well in their lessons. They liked her very much. Now the old woman stays at home with her husband. The old man looks after his life and she is 2 worried about anything. And she is very 3 . Just like some old people, Mrs Black finds that her 4 is falling. Sometimes she forgets what she did or will do. It often gets her in trouble. Her 5 noticed (注意到) it and asked her to see the famous doctor who lives in the capital. He bought two tickets (票) 6 London and told her to put 7 into her handbag while she was playing the piano. The next morning, when they got to the 8 just catch on the plane, Mrs Black said, " I wish we'd brought the 9 with us." "Don't be a fool, dear!" said Mr. Black. "We are not going to hold a concert, but see a 10 ." | ||||
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钛是一种重要的航天金属材料，小明和小强到实验室探究它的金属活动性强弱两人找到了质量相同并打磨光亮的镁、铝、铜、钛四种金属片，以及质量分数都为10%的稀硫酸和稀盐酸．
（1）为探究钛在这四种金属中的活动性强弱，你提出的假设是______．
（2）根据假设，两人分别设计了如下实验：
①小强先将镁片、钛片分别投入到200g质量分数为10%的稀盐酸中；再将铝片、铜片分别投入到200g质量分数为10%的稀硫酸中．
小强实验设计中欠妥之处是______．
②小明选择四块质量相同的金属片，分别投入到200g质量分数为10%的稀硫酸中．观察到的实验现象如下：
| 金属 | Ti | Mg | Al | Cu |
| 现象 | 有气泡产生， 但反应缓慢 | 大量气泡产生， 反应非常剧烈 | 有较多气泡产生， 反应较剧烈 | 无气泡产生， 无明显现象 |
③写出一个你所熟悉的并与该实验相关的化学方程式．