A：has not heard of
B：had not heard of
C：has not been heard of
D：had not been heard of
酒精的热值是3×107J/Kg表示____ ．
①在巴西我见到了混血儿 ②2 月下旬，我赶上了盛大的狂欢节.③在圣保罗街头我看到了比哈尔滨规模还大的冰雕艺术品.④和巴西孩子一起踢足球，使我球技大增
