It doesn't take much to work it out, the Empress hasn't been able to give birth to a son, why would she let the son of a concubine threaten her position? Mothers are only important for the sons they give you, that has remained the same from ancient times until the modern day, having a son consolidates a woman's status in her marriage.

I like Gong Li more.

Between Gong Li and Zhang Ziyi, who do you like more?

Studying that way is useless. It's still best to memorize words from the dictionary. You can increase your vocabulary. On top of that, you can attend some classes taught by a foreign teacher on the weekend and solidify your grammar. That's what I call, 'double insurance'.