题干
_____much is it ?
—It's five yuan.
A：What
B：Where
C：How
答案(点此获取答案解析）
C
—It's five yuan.
A：What
B：Where
C：How
AB＝a，
BC＝b，
CA＝c，若a·(a＋b
)＜0，则△ABC是（ ）