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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】Human beings have used tools for a very long time. In some parts of the world you can still find tools that people used more than two million years ago. They made these tools by hitting one stone agai...
A.
disastrous.
B.
unpredictable.
C.
exciting.
D.
colourful.
【单选题】Human beings have used tools for a very long time. In some parts of the world you can still find tools that people used more than two million years ago. They made these tools by hitting one stone agai...
A.
disastrous.
B.
unpredictable.
C.
exciting.
D.
colourful.
相关题目：
【单选题】光导纤维照明原理的原理是（）。
A.
嵌套原理
B.
分离原理
C.
抽取原理
D.
反向作用原理
【判断题】常温下硅晶体三极管的U错误E=约为0.7V，且随温度升高而减小。( )
A.
正确
B.
错误
【判断题】硅晶体结构中原子间结合方式属于离子键
A.
正确
B.
错误
【单选题】硅晶体结构是金刚石结构，每个晶胞中含原子个数为（ ）
A.
1
B.
2
C.
4
D.
8
【判断题】硅晶体的半导体性源于共价键。()
A.
正确
B.
错误
【单选题】光导纤维的成分是（ ）
A.
单质硅
B.
二氧化硅
C.
硅酸盐
D.
高分子化合物
【单选题】Human beings have used tools for a very long time. In some parts of the world you can still find tools that people used more than two million years ago. They made these tools by hitting one stone agai...
A.
disastrous.
B.
unpredictable.
C.
exciting.
D.
colourful.
【单选题】Human beings have used tools for a very long time. In some parts of the world you can still find tools that people used more than two million years ago. They made these tools by hitting one stone agai...
A.
disastrous.
B.
unpredictable.
C.
exciting.
D.
colourful.
【单选题】光导纤维主要利用的是光的（）原理。
A.
折射
B.
反射
C.
投射
D.
全反射
【单选题】光导纤维的主要成分是：
A.
纯硅
B.
玻璃
C.
纯SiO2
D.
沙子
【单选题】光导纤维的主要成分是
A.
纯硅
B.
玻璃
C.
SiO 2
D.
沙子
【单选题】光导纤维的主要成分是（ ）
A.
纯硅
B.
玻璃
C.
纯SiO2
D.
沙子
【多选题】硅晶体具有典型的半导体材料的电学性质,包括( )。
A.
电阻率特性
B.
整流特性
C.
光电特性
D.
欧姆特性
【单选题】光导纤维的主要成分是[ ]
A.
纯硅
B.
玻璃
C.
纯SiO2
D.
沙子