较轻的推进器采用液态氢, 较重的采用自燃推进剂.The lighter version used liquid hydrogen, the heavier used hypergolic propellants.磷化氢是一种有毒气体,在空气中可以自燃.Phosphine is a toxic gas which ignites spontaneously in air.它们也可作为自燃点火成分,改进点火和重新点火性能.They also...
Environmentally-conscious Germans are worried about the pollution the car produces.关注环境的德国人对汽车造成的污染十分担心。Our brochure is printed on environmentally-friendly paper.我们的小册子是用环保纸张印刷的。He veered away from the most environmental...
C : Wonderful! How much is a pair of antireflection lenses?那太好了! 一对不反光镜片约要多少钱 呢 ?I need to buy new spectacle frames but I will keep the old lenses.我需要买新的眼镜框, 不过我会留着旧镜片。These sandstone bodies form elongate lenses.这些砂岩体形成伸...