含强腐蚀性气体组分（）的混合气体，称为腐蚀性混合气。 不论浓度大小。 0.1%以上。 0.5%以上。 2%以上。
You execute the following RMAN command in the order shown below： BACKUP VALIDATE DATABASE； BLOCKRECOVER CORRUPTION LIST； What will these commands do？（） Create a backup of the database and recover all corrupted blocks found in the backup.。 Run a backup validation and list all the logically corrupt blocks as well as physically corrupt blocks in the database.。 Run a backup validation to populate V$COPY_CORRUPTION view， and then list any corrupt blocks recorded in the view.。 Run a backup validation to populate V$DATABASE_BLOCK_CORRUPTION view， and then repair any corrupt blocks recorded in the view.。 Run a backup validation， repair any corrupt blocks found during the validation process， and then update V$DATABASE_BLOCK_CORRUPTION view to indicate which corrupt blocks have been repaired.。
王某，20岁，不慎被金环蛇咬伤，以下哪一项不是咬伤后的临床表现（） 烦躁不安。 语言不清。 视物模糊。 皮肤粘膜出血。 肢体软瘫或麻木。
螺栓穿入方向应一致朝外且合理，螺栓拧紧后外露丝扣不小于（）扣。 1~2。 2~3。 3~4。 4~5。
简述往复式压缩机活塞的基本结构型式。
Which two statements are true about record groups?（）
