In user-managed backup and recover procedures， how are data files backed up？ （） A: Using SQL commands. B: Using SQL*Plus commands. C: Using operating system commands. D: Using Recover Manager commands.

下列shell中的循环语句结构，正确的是（） A: A. while condition then commands done B: B. while condition do commands done C: C. while : do commands done D: D. until condition do commands done

词汇与结构The system can operate independently without interfering with pilot ________ rudder commands.

A(n) ___________ is a basic program for entering commands and code into a computer.

Can rising tone be used in imperative sentences or strong commands？

72（） A: commands B: objectives C: tendencies D: claims

What does computer program mean? A: Command sequence to achieve a given task B: Collection of all commands of a computer C: Commands that the computer can recognize and execute D: High-level programming language statements

are usually used in a directional process essay to give orders, commands, , requests, etc.

Flight director commands are shown on ADI for the pilot to control or monitor the attitude of the aircraft.

Falling Tone is frequently used in ________,________,________andExclamations.? Wh-questions|Statements|Yes-no questions|Commands