To solve this problem, we must use the theorem that the sum of two sides of a triangle is greater than the third side, and then list all the combinations of sides to see if the value of A is reasonable, so as to judge whether it is true or not.

Let the three sides of a triangle be AB=a-3, BC=a and AC=a+3. According to this theorem, the following formulas can be listed:

( 1)、a b+ BC & gt； AC, that is, a-3+a >; A+3, get a>6.

(2)、a b+ AC & gt； BC, that is, a-3+a+3 >; A, get 2a >；; Answer.

(3)、BC+AC & gt； AB, namely A+A+3 >; A-3, get a & gt-6.

Based on the above results, it can be concluded that only at 6 o'clock in a>6, three line segments a-3, A and a+3 can form a triangle. At 3 o'clock