[单选] 胸外心脏按压位置在胸骨（）处。

How would the number 231 be expressed as a binary number?（） 11011011。 11110011。 11100111。 11111001。 11010011。 在Access 2000中，“货币”型数据最长为（）个字节，“自动编号”型数据最长为（）个字节。 可使无效（可撤销）婚姻的原因包括哪些？ You have a file server named Server1 that runs Windows Server 2003 Service Pack 2 (SP2). You need to use Windows Backup to meet the following requirements: ·Minimize the number of scheduled backup jobs. ·Perform a scheduled normal backup to disk every Friday. ·Perform a scheduled normal backup to tape every Friday. ·Perform scheduled differential backups to tape every Monday, Tuesday, Wednesday, and Thursday. How many scheduled jobs should you create from Windows Backup? （） one。 two。 three。 six。 企业的核心能力具有以下特性（） 快速性。 动态性。 异质性。 不可交易性。 难模仿性。 胸外心脏按压位置在胸骨（）处。