国家安全包含两层含义,即既指国家处于安全状态,也指维护这种国家安全状态的能力
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以下属于3D打印技术类型的是
A. SLA
B. FDM
C. SLS
D. 3DP
以丝状材料进行打印成形的技术类型是:
A. SLA
B. FDM
C. EBSM
D. EBF3
以下工艺类型中,属于直接熔化金属粉末成形的是:
A. SLS
B. SLM
C. EBSM
D. FDM
We often need to hear a message repeated, because we often don’t “get it” the first time. What does “get it” mean here in paragraph 1?
A. Take it
B. Understand it.
C. Put it.
D. Buy it.