Version B is an old topic, an earlier topic.

For example, it's 09. Then version A is a topic that just came out in 2009 and has been updated.

Version B is a topic before 2009.

I think when I was a freshman,

Good at math, physics, chemistry and Wang Houxiong.

I used this all the time, when I was a freshman.

In the second year of high school, Wang Houxiong's is not easy to use. I feel that the overall difficulty is relatively simple.

You can buy some books to review the college entrance examination.