他的经济实力可以撑过这次房地产市场萧条期。He can afford to sit out the property slump.尽管还处于萧条期，利润却迅猛增长。In spite of the recession, profits have galloped ahead.经济正处于萧条期。The economy is in the doldrums....
欧几里德几何的唯一性与必要性已被公认.The common conclusion was the uniqueness and necessity of Euclidean geometry.非 欧几里德几何实际上是从属于欧几里德几何的.The non - Euclidena geometries were in effect subordinated to Euclidean geometry.这种几何和Riemann几何的关系是不清...