释义
num.&n. 十亿
例句
1. It took them more than one billion dollars to complete the project.
完成这个工程花费了他们十亿多美元。
2. The human brain contains several billion nerve cells, which are connected with one another by fine nerves.
人类的大脑含有几十亿个神经细胞，这些细胞由纤细的神经将彼此连接起来。