男性，50岁。车祸致双下肢广泛软组织挫伤。人院查体：心率106/min，血压105/75mmHg，急行手术清创。术中的最佳输液原则是（） ["扩容以纠酸","扩容，碱化尿液","输血","输血浆代用品","输葡萄糖"]
Which command can be used to show volume group information about filesystems and OS levels for a specified mksysb called server1.mksysb？（） ["lsmksysb -lf server1.mksysb","restore -mrT server1.mksysb","listbackup -fT server1.mksysb","listvgbackup -l server1.mksy"]
采用电力引爆方法，装炮时距工作面（）以内，应断开电流。 ["A.20米 ","B.30米 ","C.40米 ","D.50米"]
如果某税收使低收入家庭比高收入家庭承受更大的负担，那么该税收就是（）。 ["“累进的”","“累退的”","“固定比例的”","“固定税额的&rdquo"]
You recently added a third-party application to your database and do not have access to the SQL code of this application. Database users are complaining of performance-related issues， such as increased time required to complete a query. While investigating， you discover from the STATSPACK utility that some of the memory structures have low hit ratios. You plan to resize some of the memory structures by using the Memory Advisor. For which memory structure will you fail to obtain optimal settings by using the Memory Advisor？（） [" java pool"," shared pool"," buffer cache"," program global area"]
教师为什么要进行课堂观察与课例研究？
