A job doesn't define you.怎么翻译define,整个句子怎么理解呢?

#define U8_MAX ((u8)255) 怎么理解 how do you define a love poem? #define issignal(x) ((x>=0 && x>=0) 1:0)怎么理解 #define F(a) #define A B 单片机编程：#define FOSC 1843200L是什么意思?#define是怎么用的? how do you define success How would you define happiness? How do you define cactus #define A ((a *)b) 是什么意思 #define LT(a,b) ((a) #define U8_MAX ((u8)255)后面括号怎么理解.u8乘以255吗?为什么u8放括号里面.