自凝树脂和化学固化型复合树脂的促进剂为
A．硼酸+硼砂B．硼酸C．硼酸+硼砂+氟化物D．氯化物E．硼砂十氟化物
参考答案：B
设备工程市场中最活跃的因素是（）。
A．供求机制
B．合同管理机制
C．竞争机制
D．政府监管机制
The sufferings of wind power industry in the mid-1980s in the United States could be attributed to the following EXCEPT ______.
A. oil crises of the 1970sB. the drop of oil pricesC. lack of funding for research into renewable energyD. loss of interest in wind energy as a widely-used source of energy
