当光束通过下列分散系时，能观察到丁达尔现象的是（ ）
A．矿泉水
B．稀HCl
C．CuSO4溶液
D．Fe（OH）3胶体
A、矿泉水属于溶液，用光束照射不能观察到丁达尔现象，故A错误；
B、稀HCl属于溶液，用光束照射不能观察到丁达尔现象，故B错误；
C、CuSO4溶液属于溶液分散系，用光束照射不能观察到丁达尔现象，故C错误；
D、Fe（OH）3胶体属于胶体分散系，用光束照射能观察到丁达尔现象，故D正确；
故选D．
| 短文填空。 | |
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| 根据上面的家谱，从下面方框中选择单词，并用其适当形式填空。 | |
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| Look at my 1 tree. I am Mike. I’m from the U.S.A. I have a big family. My wife (妻子) 2 is a nurse. We have 3 kids. 4 is our son and Joy is our 5 . They study at No.1 High School. My father’s name is Bill and my 6 name is Helen. My 7 are very old. John is my 8 . He is a doctor. Kate is my wife’s 9 . She is a teacher. Emma is my wife’s mother. My wife’s 10 is Peter. They’re old, too. They don’t go to work and they are often at home. |