A successful businessman was invited to a TV

小题1: . Everybody couldn’t wait to hear a success story from him. He, however, only said  小题2:, “Won’t it be better for me to ask you for help on a certain problem？”

Here was his problem. “ People all rushed to the place where a gold mine(矿) had just been   小题3: , but there was a deep river stopping them. They must cross the river if they wanted to get to the gold mine. What would you do if you were among them? Please give me some 小题4: .”

妊娠雌激素主要来自______及______。