比邻星是距离地球最近的恒星，从比邻星发出的光约4.3年才能到达地球，则比邻星距地球约 _________ km．
4.1×1013Km
______ of our good taste, we are no longer free to choose things we want.
A．So proud may we be
B．Although we may pride ourselves a great deal
C．Proud as we may be
D．Pride ourselves as we may
新氢中的惰性气体含量大小对加氢裂化过程（）
Ａ、不利
Ｂ、无影响
Ｃ、有利
