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问题 问答题

现有①铁②冰水混合物③医用75%的酒精④氢气⑤液态空气⑥矿泉水六种物质，其中属于混合物的有（填序号，下同）______，属于纯净物的有______．

答案

医用75%的酒精、液态空气、矿泉水都是由不同种物质组成的，都属于混合物．

铁、冰水混合物、氢气等物质都是由一种物质组成的，属于纯净物．

故填：③⑤⑥；①②④．

选择题

新航路开辟后，最先侵入拉丁美洲，进行殖民掠夺、殖民统治的欧洲国家是[ ]

A．英国和法国

B．西班牙和葡萄牙

C．法国和荷兰

D．英国和荷兰
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单项选择题

Almost everyone likes dogs, and almost everyone likes to read stories about dogs.
I have a friend. He has a big police dog named Jack. Police dogs are very clever. Every Sunday afternoon my friend takes the dog for a long walk in the park. Jack likes these long walks very much.
One Sunday afternoon, a young man came to visit my friend. He stayed a long time. He talked and talked. Soon it was time for my friend to take Jack out for a walk. But the visitor still stayed. Jack became very worried. He walked around the room several times and then sat down in front of the visitor and looked at him. But the visitor paid no attention. He went on talking. At last Jack got angry. He went out of the room and came back a few minutes later. He sat down again in front of the visitor, but this time he took the visitor’s cap in his mouth.

Jack became worried because ______.

A. he want’ed to go out for a walk
B. he wanted to play with the young man
C. he didn’t know the young man
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