clever

她很聪明。

She's ___clever.

他的弟弟比他更聪明，学东西更快。

His younger brother is ___cleverer than him and learns things faster.

我的妹妹很聪明，她五岁就能读书了。

My sister is very ___clever; she could read when she was five.

这个谜语很巧妙，你能猜出答案吗？

This riddle is very ___clever. Can you guess the answer?