价格协调在下面（）情况可能发生.
A.市场集中度低
B.厂商数量多
C.成本差别大
D.产品差别化程度小
参考答案：D
I’m sorry I can’t help ____ the flowers, because I’m busy preparing for the singing competition ____ tomorrow.
A．watering; to be held
B．water; being held
C．to water; held
D．water; to be held
What on ____ earth are you doing under such ___ burning sun? Go indoors.
A．the; the
B．an; a
C．/; /
D．/; a
