政府采购的主要采购方式是（）。
A．公开招标
B．邀请招标
C．竞争性谈判
D．询价
参考答案：A
It is said that some software on learning subjects for pupils _______ in a very practical way. [ ]
A. designed
B. is designed
C. designs
D. is designing
玉米的储藏方法与管理措施？
