如图所示，固定的水平光滑金属导轨，间距为L，左端接有阻值为R的电阻，处在方向竖直

某家庭装饰厨房需用480块某品牌的同一种规格的瓷砖，装饰材料商场出售的这种瓷砖有大、小两种包装，大包装每包50片，价格为30元；小包装每包30片，价格为20元，若大、小包装均不拆开零售，那么怎样制定购买方案才能使所付费用最少?

根据短文内容及首字母的提示，填写所缺单词。

Mr. Martin went into a coffee shop one morning, and sat a 小题1:. Many others came in, but most of them did not stay long.

After fifteen m小题2:, a young man and a young woman came in. There were only two e 小题3:  seats at the counter, one on Mr. Martin’s left, and the other on his r小题4: .So Mr. Martin offered  to change places w小题5: the man, so that the man and the young woman could be t小题6:.

“Oh, that isn’t necessary,” the young man said. But Mr. Martin still wanted to c小题7:. When  they were side by side, the man said to the woman, “Well, this gentleman wanted us to s 小题8:  together, so may I introduce m 小题9: ? My name is Tom. What’s y小题10:?”

省煤器漏泄现象？

显微鉴别的方法包括组织鉴定、（）、显微常量测定、（）、显微定量等

在基于Web 的电子商务应用中，业务对象常用的数据库访问方式之一是 （58） 。

A．JDBC

B．COM

C．CGI

D．XML