问题
单项选择题
普通混凝土中每立方米混凝土的最大水泥用量不应超过（）。
A、230ｋｇ
B、400ｋｇ
C、450ｋｇ
D、500ｋｇ
答案
参考答案：B
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普通混凝土中每立方米混凝土的最大水泥用量不应超过（）。
A、230ｋｇ
B、400ｋｇ
C、450ｋｇ
D、500ｋｇ
参考答案：B
| 完形填空。 | ||||
| Many objects that people use each day started with a simple idea. These objects have often changed the way we 1 . Some help us to do a job more 2 . Others fill a need or solve a problem. In 1858, Lipman had such an 3 . He took out a pencil, a piece of paper, 4 an eraser. Then he began to write. Sometimes he needed to 5 a word. Each time he had to search under his books and papers to 6 the eraser." I wish my eraser would stay in one 7 !" he said. Then Lipman had his simple idea. He 8 a groove (凹槽) in one end of the pencil. He glued (粘牢) the eraser into the groove. Lipman had solved his problem. Later he thought that others might like to have such a pencil. So he sold his 9 . Some pencils with erasers were 10 . His design earned $ 100000. | ||||
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