下列公式中,投入的物料在生产过程中发生化学反应时的总物料衡算计算方式()
AD=BD—(aD+bD+cD+Dd)
B. ∑G投入=∑G产品+∑G流失
C. ∑G排放=∑G投入-∑G回收—∑G处理—∑G转化—∑G产品
D. Q+A=H+P+L
Which of the following is the main topic of the passage?
A. Scientists and their curiosity.
B. Science and scientific method.
C. Understandings of science.
D. Misunderstandings of science.
某供应商关系模式为:
Providler(PID,Pname,Tel,GoodsID,GoodsClas-sID, GoodsName,GoodsPrice)
该关系模式应满足以下函数依赖:
PID→Pname,PID→TEL,GoodsID→GoodsClassID,GoodsID→GoodsName,GoodsName→GoodsPrice
则这个关系模式的主码为______。
A. (PID,GoodsName)
B. (PID,GoodsClassID)
C. (PID,GoodsI)
D. (PID,GoodsPric)
Basically the author's opinion of Washington is______.
A. praiseful
B. derogatory
C. critical
D. negative