Sulphur has {{U}}occasionally{{/U}} been found in the earth in an almost pure state.

题库:综合类 类型:最佳选择题 时间:2017-07-03 03:15:37 免费下载:《单选题》Word试卷

Sulphur has {{U}}occasionally{{/U}} been found in the earth in an almost pure state.
A.regularly
B.accidentally
C.sometimes
D.successfully

本题关键词:肛I,石I鱼,因子I,I因子,I导联,I度烧伤,I类抗原,I期愈合,I类分子,I类环境;