A female giant panda produces about one to two cubs biannually , so strengthening the wild population is a difficult and slow process .
一个雌性大熊猫每两年约生产一至两只幼崽,因此,增大野生种群是一个艰难而缓慢的过程。
Since the war , important festivals have been held annually or biannually in berlin , london , moscow , prague and czechoslovakia .
二战以来,每年或每两年便有重要的电影节在柏林,伦敦,莫斯科。布拉格和捷克斯洛伐克举行。
Aircraft makers from around the world gather biannually at the farnborough international air show to display their latest technologies and secure orders for their products .