题干
根据句子意思，用括号中所给词的正确形式填空，每空填一词。
Seven ____ (twelve) of the students have taken part in the tree-planting activity since Monday.
答案(点此获取答案解析）
twelfths
根据句子意思，用括号中所给词的正确形式填空，每空填一词。
Seven ____ (twelve) of the students have taken part in the tree-planting activity since Monday.
作为标准，发现Ra元素的居里夫人(Marie Curie)曾两度获得诺贝尔奖。下列叙述中正确的是