Keep Watch Over Your Woman!

Besides, her plan is to use Lu Beichen to get closer to Lu Sichen....

Lu Beichen frowned when he remembered Li Ran's attitude to him. She wasn't like this in the past. In the past, she was always following behind him like a lost animal who had nowhere to go. If he told her to go left, Li Ran wouldn't dare go right! 

When did things start to change? Maybe it was when Lu Sichen asked for her hand in marriage? 

No....Lu Beichen remembered that when Lu Sichen asked for Li Ran's hand in marriage, Li Ran was so angry that she refused to go home for a few days. So it can't be then.