果园里种了80棵苹果树,比种的梨树的3倍多20棵,种了梨树多少棵?(列方程解答)
设梨树种了x棵,由题意得,
3x=80-20,
3x=60,
x=20.
答:种了梨树20棵.
Within the context of the UN Convention on Contracts for the International Sale of Goods, explain the obligations imposed on the buyer of goods. (10 marks)
为保证“炒炭存性”,经研究荆芥炭应从哪几个方面来控制饮片质量()
A.内外颜色
B.水分含量
C.灰分含量
D.浸出物含量
E.挥发油含量及折光率