膨胀水箱的作用是什么
参考答案：防止水在受热后体积膨胀而胀坏管道和设备，向系统补水，排除系统空气，指示系统水位及为系统定压。
(c) Assuming that the rate of sales tax on the low-priced polythene bags is increased from 16% to 20% effective from 23 December 2009:(i) State the manner in which the sales tax return for the month of December 2009 would need to be furnished; (2 marks)(ii) Calculate the sales tax payable by Hamza Usman & Sons for the month of December 2009. (5 marks)
只能由______取消该凭证审核的签字。
A．制单人
B．数据分析员
C．系统管理员
D．该凭证的审核人
