A: He took French leave yesterday.
B: How come?
A: It's said that she was tired of his family.
B: I don't think so.
take French leave
Take French leave的意思是“不辞而别”“擅自离开”，相当于“to leave without say goodbye”。
E.g. He took French leave when the party was in full swing.
E.g. He take on his hat and then take French leave.
E.g. I wanted to go the football match, and so I took French leave from the office. Unfortunately, the boss found out.
It's said that......：据说
E.g. It is said that the police monitored his phone calls during that period.
E.g. It is said that there has been a big earthquake in Italy.
E.g. If she spent five years in Paris, how come she can't speak a word of French?
E.g. Cindy, how come nearly all the prime-time TV shows are comedies?