The 30′s were not less invention-intensive bringing us the jet engine, helicopter, tea bags, sticky tape, ballpoint pen and the first photocopier.

30年代人们也有不少发明，如喷气发动机、直升机、泡茶袋、胶带、圆珠笔和第一台复印机。

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Management decided to take a measured approach, selling off smaller defense units such as the Norden electronics business (bought by Westinghouse in 1994) while retaining the engine and helicopter businesses.

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The witness said he did not hear any irregular engine noise when the helicopter went past and the height and speed of the craft were normal.

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But the witness told the court there was no sign of engine problems at the point when he saw the helicopter.

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