Even a casual observer could hardly have failed to notice the heightening of an already tense atmosphere.即便是不经意的旁观者也一定已经觉察到本就紧张的气氛进一步加剧了。Teachers can help build students' vocabulary knowledge by heightening their interest in words.老师们可以通过提高学生们对单词的兴趣来帮助他们构建词汇知识。