A geomantic contest for the palace
Secondly, he didn't want to reveal the secret. People who do divination have their own unique skills. They generally don't like to tell others what they have worked out, unless they are charlatans who make money from it. They must tell others the results of their calculations. And the Wu Zetian he faces, if he doesn't tell Wu Zetian then, will definitely be killed. So he thinks we should solve this matter from the root, that is, don't calculate her.
In the end, I never gave her divination, so that Wu Zetian had a feeling that he still had use value, so that she would not kill him easily. It can be said that everyone in the palace was struggling for survival at that time, and he was no exception. He chose not to predict Wu Zetian in order to save his life. Emperors generally connive at people who will be of use again and again, and so does Wu Zetian. So he will give Wu Zetian the illusion that he still has use value. .......................
In a word, he didn't plan Wu Zetian because he didn't want to die.