题干
改错
—“Where is he ?”
—“He has been to Paris.”
____
答案(点此获取答案解析）
been 改为 gone
改错
—“Where is he ?”
—“He has been to Paris.”
____
是非空集合，定义集合
为阴影部分表示的集合．若
,则
要说明 （ ）