2008年3月20日，曲靖市商业银行个人信用信息基础数据库正式上线运行。银行业金

买单价为x元/千克的苹果2y千克共需______元；这个式子的系数为______，次数为______．

写出下列化学用语：

（1）由甲烷制取一氯甲烷的化学方程式：__________________________

（2）写出异丁烷的结构简式                        。

The vast differences in the ways students learn are often_____when they are taught the same thing, in the same way, at the same time. Therefore many of them feel little enthusi astic and even hostile for the ways instruction is handled.

A．disregarded

B．distinguished

C．discharged

D．discerned

离子晶体

不属于后天性二尖瓣病变的是

A．风湿性二尖瓣狭窄
B．二尖瓣脱垂
C．二尖瓣腱索断裂
D．二尖瓣钙化
E．二尖瓣闭锁