铝、铜、钛、碳钢四种金属材料中,熔点最高的是()。 ["A、铝","B、铜","C、钛","D、碳钢"]
活塞式压缩机的十字头与滑道的间隙值应该用()测量,但其间隙应保持两侧均匀。 ["A、塞尺","B、外径千分尺","C、块规"]
信道号为1020的EGSM载频,其对应的下行频率为()。 ["943","934.2","943.2","1020"]
延度试验水浴时水浴内搁架距水浴底部不得小于()(cm)。 ["A、2","B、3","C、4","D、5"]
粉煤灰需水量比试验中,试验胶砂的流动度应达到()。 ["110mm~120mm","120mm~130mm","130mm~140mm","140mm~150mm"]
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