未知题型 听力原文：For most of their lives, the two men had shared confidences, swapped advice and supported each other's ambitions. The dozens of letters that Justice Blackmun saved document a relationship of sometimes startling intimacy.The two men have been very intimate and reliable friends throughout their lives.A．正确B．错误

单项选择题 增值税是我国政府对从事进口贸易的单位和个人，在进口商品报关进口后征收的税种，增值税基本税率为（ ）。 A．0．5% B．1．5% C．15% D．17%

单项选择题 某建材厂设计能力为年生产某型号预制构件7200件，每件售价5000元，该厂固定成本680万元，每件产品变动成本为3000元，则该厂的盈亏平衡产量为（ ）件。 A．3500 B．3000 C．4420 D．3400