单项选择题 Please compare Letter A with Letter B, and comment on both of them. Then, revise your favorite one for effectiveness. Add any information if necessary. Letter A Dear Mr Hope Further to your order of 12 July 2019, we have today dispatched to you some soft cotton materials to the value of USD $ 50000 . We present our Bill of Exchange, drawn on you for this sum at 3 months from today’s date, for acceptance and return. We hope your business goes well. Yours sincerely Sara Smiths (Ms) Letter B Dear Mr Hope Thank you for your order of 12 July 2019. We have today dispatched to you 2000 rolls of cotton materials to the value of USD $ 50, 000 . We enclose our Bill of Exchange, drawn on you for this sum at 3 months from today’s date, for your acceptance and return to us. May we take this opportunity of wishing you every success in your new business. Yours sincerely Sara Smiths (Ms)

未知题型 接触网打冰，处理鸟窝、异物可在天窗点外进行，但严禁利用速度160km/h及以上的列车与前一趟列车之间的间隔时间作业（）

未知题型 在页式存储管理中，页表如下。若页的大小为4KB，则逻辑地址0转换成物理地址是多少？ 页号 块号（页框号） 0 2 1 1 2 6 3 3 4 7