adj.无效的，零值的，等于零的
n.数字零，空位，空白符号，无信号

The variable remained null after the user input.
用户输入后，变量仍然为null。
She hasn't responded to my email, so her address is currently null.
她还没有回复我的邮件，所以她的地址现在还是null。
In programming, a null value indicates an uninitialized or empty variable.
在编程中，null值表示未初始化或空的变量。
NullPointerException occurred when trying to access a null object reference.
尝试访问null对象引用时发生了NullPointerException。
The database query returned null for the requested data.
数据库查询请求的数据返回了null。
A null hypothesis in statistics is that there is no significant difference between groups.
统计学中的零假设是没有组间显著差异。
The function returned null when no matching element was found in the array.
当数组中没有找到匹配元素时，函数返回了null。
He set his expectations to null before starting the new job, so he wouldn't be disappointed.
他开始新工作前设定了无期待，这样就不会感到失望。
The memory location assigned to the pointer was null, causing a crash.
指针分配的内存位置是null，导致了崩溃。
Her response to the question was null, meaning she had no answer.
她对这个问题的回答是null，即她没有答案。