compressed air and nitrogen
helium and nitrogen
oxygen and hydrogen
oxygen and acetylene
第1题：
______ the most versatile of the common metals, lead was widely valued and used in ancient times.
A. It is
B. Therefore
C. Among
D. Because
第2题：
A. System privileges apply only to the PDB in which they are used.
B. Local users cannot use local system privileges on the schema of a common user.
C. The granter of system privileges must possess the set container privilege.
D. Common users connected to a PDB can exercise privileges across other PDBs.
E. System privileges with the with grant option container all clause must be granted to a common user before the common user can grant privileges to other users.
第3题：
此题为判断题(对，错)。
第4题：
Which statement is TRUE concerning inert gas systems on tankers ________．
A.Flue gases from the ship's boilers are used in some systems
B.The gas is helium
C.Using the system accelerates the rusting of the tanks
D.All of the above
第5题：
The display screen is the most common (72) device used to show you what the computer is doing．
A．input
B．printing
C．output
D．electronic
第6题：
A.are the most three common means
B.are the most common three means
C.are the three most common means
D.are three the most common means
第7题：
A. clear system login
B. boot -s
C. recovery
D. delete system root-authentication
第8题：
The most widely used LAN system is ______ which adopts a form. of access known as CSMA-CD．
A．Ethemet
B．ATM
C．FDDI
D．Wireless
第9题：
The use of sinking and dispersing chemical agents for removal of surface oil is ______.
A.the most common method used in the United States
B.too expensive for common use
C.generally safe to sea life
D.authorized only with prior approval of the Federal On-Scene Coordinator
第10题：
NAS， SAN， and Tape library are MOST commonly used for which of the following？（）