"My mother is 45 years old" 的英语表达方式为 "My mother is 45."
来源：这是一种常见的表达方式，用于描述某人的年龄。
例句：
"My mother is 45 and she still works as a nurse." (我的妈妈今年45岁，她仍然是一名护士。)
"My dad is 50 and my mother is 45. They have been married for 25 years." (我爸爸是50岁，我妈妈是45岁。他们已经结婚25年了。)
翻译：
"My mother is 45 and she still works as a nurse."（我的妈妈今年45岁，她仍然是一名护士。）
"My dad is 50 and my mother is 45. They have been married for 25 years."（我爸爸是50岁，我妈妈是45岁。他们已经结婚25年了。）