Among the following options,（）is not the source of the SDH clock
A. External clock source
B. Internal clock source
C. The clock extracted from optical links
D. The clock extracted from network management system
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The ZXMP S320 device provides a synchronization scheme based on SSM information. The main function of this scheme is（）
A. Select the effective timing source with the highest synchronization quality
B. Prevent the clock from forming a loop
C. Guarantee the timing synchronization performance of the network
D. All of the above are correct
Since she hasn’t achieved her goal set by the company yet, she knew that a holiday this year is ______（）
A. out of the question
B. out of question
C. without the question
D. without question
合成DNA的原料有（）
A. dAMP dGMP dCMP dTMP
B. dADP dGDP dCDP dTDP
C. dATP dGTP dCTP dTTP
D. AMP UMP CMP GMP
What is digital educational technology（）
A. Traditional classroom
B. Chalkboard
Chalk
D. Computers
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