According to defend thunder to be grade different, there is different protection radius, has introduced the computing technology.

根据防雷等级不同，有不同的保护半径，并介绍了计算方法。

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Once a complaint is filed, the professor usually has to undergo a prolonged accusatory process to defend the grade.

ECONOMIST: Silvio Berlusconi

The real pressure to introduce another grade was from politicians, she suggested, who wanted to defend themselves against accusations of exams getting easier.

BBC: Top head attacks grade change stress