1.In 1990,it ___ more than five billion.
问题描述：
1.In 1990,it ___ more than five billion.
2.Now at the beginning of the 21st the world's population ___ six billion.
3.four hundred years ago,the number___over 500 million.
用reach 、pass 、be 填空.尽量不要用重复的词填空.
答
was
has reached
was