The world's population is ---------500 million.A .nearly B.almost 选哪一个,为什么?

A.接近的意思请告诉我理由好吗？nearly , almost 虽然都可以表示“几乎”，但是当要表示“接近”或“就要到了”时最好用nearly；当想表达“不足”或“尚差一点儿”时最好用almost I had nearly reached town, when the young man suddenly said, very slowly, "Do you speak English? " 我几乎就要到达城镇了，这时那位年轻人突然非常慢地说道：“你会说英语吗？” The ball struck him so hard that he nearly fell into the water. 那球重重地打在他身上，他几乎掉下水去。 He's only forty-one years old, and he has already been to nearly every country in the world. 他只有41岁，而他几乎已经到过世界上一切国家。 Dreams of finding lost treasure almost came true recently. 寻找丢失的金银财宝的梦想最近几乎实现了。 She enjoyed herself making the assistant bring almost everything in the window before finally buying the dress she had first asked for. 她开心地迫使这位售货员几乎把橱窗里的每样东西都拿了出来，最后才买下她开始时要的那件衣裙。 注：有时almost和nearly可以换用，但如果要表达“差一点儿”还是用almost确切 I almost fell down. 我差一点儿没跌倒。 The speaker said almost nothing worth listening to. 那位演说人几乎没有说出什么值得听的东西。 注：句中有no, none, nothing, never等词时，不可以用nearly，但可以用almost针对本题用almost又错在哪里？谢谢nearly侧重指数量、时间或空间上的接近。