natural deduction proof procedure 自然演绎证明过程
proof deduction
证据推理
以上为机器翻译结果，长、整句建议使用 人工翻译 。
The cellphone substantiation provision was needed because the Internal Revenue Service has strict, congressionally ordered rules requiring proof you made a donation if you want to take it as a tax deduction.
FORBES: Charitable Giving
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