Missus Obama joked that if she had known, she would have picked a higher number.

VOA: special.2010.05.28

Agricultural villages will have existed all over the place in the late Stone Age, in the Neolithic Period, as it is known. But there is a difference and the critical difference is that a city contains a number of people who do not provide for their own support.

农业村庄在石器时代后期,以及新石器时代随处可见,但二者是有区别的,最重要的区别在于,城市能容纳,相当数量,无需自给自足的人口

耶鲁公开课 - 古希腊历史简介课程节选

The real number of people he killed will never be known.

VOA: special.2010.03.17

Security experts say armed Maoists, also known as Naxalites, number about 20,000 and control about one-fifth of India's forests.

VOA: standard.2009.06.21

While the crises in these three countries are relatively well known, there are a number of countries that remain largely forgotten.

VOA: standard.2010.02.04

The exact number of foreigners in Somalia is not known.

VOA: standard.2009.12.23