Fermat"s last theorem has been called the most ______ problem in all mathematics: for over 350 years, the conjecture ______ mathematicians, until it was finally proven in 1995.

多项选择题While many educators have hailed the new documentary about climate change as a ______ for teachers interested in engaging their students on the issue, such enthusiasm is far from ______.

多项选择题Edgar s ______ at having bungled the simple assignment was clear from his trembling lips and averted eyes.