一台光驱使用了两年,最近出现了问题,就是无论什么样的光盘放进光驱都不能读取信息,而且能听到光驱在每一次读盘前少许“嚓嚓”的摩擦声,然后指示灯亮一会儿就熄灭了。后来清洗了激光头,故障仍不能排除,调大光头的功率也不管用,请问这可能是什么原因造成的?该如何解决?
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患者男,75岁,因“记忆力减退2年加重1个月”来诊。患者2年前无明显诱因出现记忆力减退,近1个月加重,尤其短期记忆减退明显,患者表情淡漠,终日寡言,计算能力明显下降,曾因找不到家走失。舌胖嫩而淡、边有齿痕、苔白厚而腻,脉滑。颅脑MRI未见明显改变。最有可能的诊断为()
A. 阿尔茨海默病
B. 血管性痴呆
C. 额颞叶痴呆
D. 抑郁症
E. 帕金森病
F. 脑积水痴呆
对纳税人销售自产货物、提供增值税劳务并同时提供建筑业劳务的,应重点审核其建设行政部门批准的建筑业施工(安装)资质证书和签订建设工程施工总包或分包合同,查阅总包或分包合同中是否单独注明建筑业劳务价款,如果不符合税法规定,其取得的混合销售收入应全额征收增值税。
A. 正确
B. 错误
Your database is functional with peak load for one hour. You want to preserve the performance statistics collected during this period so that they can be used for comparison while analyzing the performance of thedatabase in the future. What action would you take to achieve this task?()
A. Set the STATISTICS_LEVEL initialization parameter to AL
B. Create a baseline on a pair of snapshots that have the statistics of the peak-load period in the database.
C. Decrease the snapshot interval in the AWR to collect more number of snapshots during the peak-load period.
D. Set the snapshot retention period in the Automatic Workload Repository (AWR) to zero to avoid the automatic purging of the snapshots.