（A）x = (a = 1,b = a + 1)

（B）i = j == 0

（C）(char)(65 + 3)

（D）x + 1 = x + 1

（A）'a' <= c <= 'z'

（B）(c >= 'a') || (c <= 'z')

（C）('a' <= c) and ('z' >= c)

（D）(c >= 'a') && (c <= 'z')