zero object

例句：

1. 1. The number of zeros in the sequence is 25.
   序列中零的数量是25。
2. 2. The zero was the only thing that could be counted.
   零是唯一可以被计数的东西。
3. 3. The zero in the equation represents a missing variable.
   方程中的零代表一个缺失的变量。