Whats the main task for "Deep Impact" this time？
A. To visit other planets.
B. To destroy the comet.
C. To collect scientific data.
D. To test the possibility of unmanned spaceship.
查看答案
下面那些影响光纤的衰减()
A信号强度
B线路衰减
C接收机灵敏度
D中心频率
E插入损耗
What can we know according to the passage？
A. Great glaciers are very destructive.
B. All glaciers move southward.
C. The Mississippi-Missouri-Ohio system is larger than it was before the Ice Age.
D. The Great Lakes are now smaller than they were before the Ice Age.
下列说法不正确的是()
A靠近闹市区的拉线加装绝缘子
B10kv两侧防雷地线断开50MM
C地锚应埋设牢固,拉线地锚应垂直于地面
D光纤固定接头采用熔接法
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