涂料组成成分中，次要成膜物质的作用是( )。
A．降低黏度便于施工
B．溶解成膜物质，影响成膜过程
C．赋予涂料美观的色彩，并提高涂膜的耐磨性
D．将其他成分粘成整体，并形成坚韧的保护膜
参考答案：C
解析：次要成膜物质不能单独成膜，它包括颜料与填料。颜料不溶于水和油，赋予涂料美观的色彩。填料能增加涂膜厚度，提高涂膜的耐磨性和硬度，减少收缩，常用的有碳酸钙、硫酸钡、滑石粉等。
Jack worked in a shop that sold clocks. He was always telling Harry 26 a new clock. But Harry, 27 lived next door to Jack, said he didn’t need one. “ 28 needs a clock,” Jack said. “How do you know when it’s time to get up?” “My landlord Mr. Smith turns on his radio at seven o’clock and listens 29 the news,” Harry said. “That’s my morning call.” “Ok. But how do you know when to go to work?” “By the time I 30 my breakfast, it’s eight o’clock, time to leave for the office. Then I walk there. When I arrive at my office, it’s nice o’clock. That’s 31 time I start work.” “Ok. But how do you know when it’s time to go home?” “The factory bell 32 ” Harry told him. “But how do you know when it’s time to go to bed?” “The television programs come to end.” By now Jack was really 33 . “Ok,” he shouted. “Now tell me what would happen 34 you woke up in the middle of the night and wanted to know the time.” “That’s easy,” Harry said, “I would knock heavily on 35 wall. Then you would shout at me, ‘What are you doing knocking on my wall at three o’clock in the morning?’”
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