问题
单项选择题
滤线栅铅条高度与其间隔之比为
A．栅比
B．栅密度
C．铅容积
D．栅焦距
E．滤线因数
答案
参考答案：A
解析：滤线栅铅条高度与其间隔之比为栅比。
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滤线栅铅条高度与其间隔之比为
A．栅比
B．栅密度
C．铅容积
D．栅焦距
E．滤线因数
参考答案：A
解析：滤线栅铅条高度与其间隔之比为栅比。
A first-grade student whose best friend is battling cancer thought that hours of playing and telling jokes was not enough - he wanted to show his buddy just how he understood the time he was going through. Seven-year-old Vincent Butterfield the only way was to cut off his hair in support of his best friend Zac who lost his hair through chemotherapy(化疗). Zac Gossage is receiving treatment but goes to Union Central Elementary School in Missouri every day, that's where he gets to play on the swing with Vincent. Vincent found out that Zac might his hair because of the chemotherapy treatment. So one day, he showed up in the first grade class wearing a . He said to his teacher Mrs. Koester, "I have a surprise for Zac." And he pulled off his cap and other saw that he already had all his hair off. "I did it just to make Zac feel he's not the only one without any ." said Vincent.Vincent has also been raising money for his best friend after learning how his chemotherapy treatments are. He asked his mother to make than 20 scarves and gloves. He and his mother them at the price of 10 dollars each, raising over $200 for Zac. The encouragement from Vincent seems to be working. Though Zac is receiving treatments, he has missed any days of school. He knows that Vincent is out on the playground, waiting for him at break. When asked friendship was, Vincent looked at his friend Zac, thought for a(an) and responded,"It's a beautiful thing." Clearly, wisdom doesn't always come with age.
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