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问题 选择题

现有

+1
H
、
+1
Na
、
+6
S
、
-2
O
四种元素，假定他们按二种或三种元素相结合形成化合物，按指定化合价最多可形成化合物的种数是（　　）

A．8种

B．7种

C．6种

D．5种

答案

若二种元素组成化合物，则有

+1
H
、
-2
O
形成水，
+1
Na
、
-2
O
形成氧化钠，
+6
S
、
-2
O
形成三氧化硫；

若三种元素组成化合物，则有

+1
H
、
+1
Na
、
-2
O
形成氢氧化钠，
+1
H
、
+6
S
、
-2
O
形成硫酸，
+1
Na
、
+6
S
、
-2
O
形成硫酸钠，

即按指定化合价最多可形成化合物的种数为6种．

故选C．

阅读理解

阅读理解。

      What's the weather like today? It's sunny, windy and warm. I go to meet my pen pal — a girl from Dalian,

in the City Zoo. The zoo is between a supermarket and a library. My pen pal's name is Lingling. She is thirteen

years old and she wants to be an animal feeder (饲养员). She loves animals very much. Now we are watching

elephants playing. They are funny and clever. There are many people in the zoo. They like to see animals. A boy

is feeding a koala. But the animal feeder stops him. We have a good time today.

1. The weather today is ______. [ ]

A. cloudy, windy and warm.

B. rainy, windy and cold.

C. sunny, windy and warm

D. sunny, cloudy and cool.

2. Ling ling is from ______. [ ]

A. Hainan

B. Shanghai

C. Taiyuan

D. Dalian

3. The zoo is ______. [ ]

A. across from a hotel

B. between a supermarket and a library

C. next to a post office

D. in front of a pay phone

4. What does Lingling want to be? [ ]

A. A doctor

B. A teacher

C. a nurse

D. An animal feeder

5. Which is wrong? [ ]

A. People can feed koalas in the zoo.

B. Lingling loves animals.

C. We can see elephants in the zoo.

D. Ling ling is a girl and she is 13.

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单项选择题 A1/A2型题

下列影响因素，主要影响外部效度而对内部效度影响不大的是（）。

A.自变量和因变量的定义

B.被试的选择

C.测验手段

D.实验程序的影响

E.研究情境与实验情境的相似性
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