这是平行四边形的对边.These are the opposite sides of the parallelogram.环面可由矩形把其两对对边分别重叠起来而得到.A torus can be obtained from a rectangle by identifying opposite sides.当各块板块彼此分离时, 他们又在对边与其它板块发生碰撞.As the plates move apart, they encount...
Astigmatism can occur in addition to nearsightedness and farsightedness.散光可发生在除近视和远视.Such farsightedness is, alas , only a drop in the bucket.可惜,这些远见只是杯水车薪.FARSIGHTEDNESS is an asset whose value should not be underestima...