Discusses the work principle and testing methods of line trap and combined filter, points out the important meaning of developing field test of line trap and combined filter.

讨论阻波器、结合滤波器的工作原理及测试方法，指出开展阻波器及结合滤波器现场测试的重要意义。

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It was Paul Collingwood who made the breakthrough, ironically with an off-cutter, to trap Kamran marginally on the line of off-stump when sweeping, while Hafeez was bowled via the inside edge and pad off Graeme Swann, who found some spin and was relatively economical.

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Meanwhile, the elegantly restrained, two-story Chinese restaurant Lu Yu, courtesy of LTW, avoids the trap of obvious chinoiserie: Stacked abacuses line a wall near the entrance, while pale celadon porcelain bricks adorn the upstairs entryway.

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With the game won Vicente del Bosque made changes and the introduction of Cesc Fabregas almost lifted the roof off Ellis Park when, 16 seconds after being introduced, he beat the offside trap and rounded the keeper only to see his shot hacked off the line by Chavez.

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