他的生日正好处于天蝎座和射手座交界的那一天。

His birthday falls on the ___cusp between Scorpio and Sagittarius.

小心别被纸的边缘划伤手指。

Be careful not to cut your finger on the ___edge of the paper.

她正处在职业生涯的高峰与低谷之间的转折点。

She is on the ___cusp between the peak and the downturn of her career.