The obliquity of the ecliptic is the fundamental cause of the seasons.黄道的倾角是季节的基本成因.First, we know that the planets all orbit close to the earth's orbital plane, the ecliptic.首先, 我们知道所有行星的轨道都很靠近地球的轨道平面――黄道面.Five bri...
Only children whose parents are existing savers may open an account.只有现有储户的孩子可以开立账户.'Sight Savers', founded in 1950, now runs projects throughout Africa, the Caribbean and South East Asia...创始于 1950 年的国际防盲及救盲组织...