动词短语
中文翻译：证明是无效的
同义词：
['prove to be', 'prove to be ineffective', 'prove to be unreliable']
例句：
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1. The new policy was proved to be ineffective in the long run.
新政策最终证明在长期内是无效的。
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2. The scientist's theory was proven to be unreliable after further testing.
科学家的理论在进一步测试后被证明是不可靠的。
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3. The company's product was proven to be unsafe during the manufacturing process.
公司在生产过程中证明产品不安全。