For an example, it took her 18 sessions to graduate to five numerals.Many monkeys needed over 50 sessions to get there.Poor old lemurs required over 500 sessions.

• 举个简单的例子，罗妮只需要18个“课时”就能掌握5个数字的排序，许多猴子需要超过50个“课时”才能完成这个任务，而狐猿需要的时间超过500个“课时”。