Mastered counts as known everywhere (frontier, map, extension) but never appears in the quiz again. New wipes the review history for this item.
例文 · examples
医者は彼に喫煙の危険性を警告した。
The doctor warned him of the dangers of smoking.
その物理学者は核融合の潜在的な危険性に気づいていた。
The physicist was aware of the potential danger of nuclear fusion.
医者は彼にその薬の危険性を警告した。
The doctor alerted him to the riskiness of the medicine.
戦場に赴くカメラマンが不発弾の危険性を知らないのは不思議だ、新聞社は教育を怠ってる。
It is strange that a cameraman heading for a war-zone should not know about the danger of unexploded shells. The newspaper company is being negligent in its training.
不発弾の危険性もあることから警察に通報し、現場にテープを張って立ち入りを防いでいる。
There's also the danger of unexploded bombs, so they reported it to the police and the area was taped off to keep people out.