题干
——We'll have a day off！
—— . That's great!
A：Is that so？
B：Thanks a lot.
C：With pleasure
D：Is that all?
答案(点此获取答案解析）
A
——We'll have a day off！
—— . That's great!
A：Is that so？
B：Thanks a lot.
C：With pleasure
D：Is that all?
，确定的可行域D能被半径为1的圆面完全覆盖，则实数
的取值范围是（ ）