It was very thoughtful of you to send the flowers.

　　你送花來，想得真周到。

　　This intriguing book is both thoughtful and informative.

　　這本引人入勝的書既有思想性又有知識性。

　　Nancy, who had been thoughtful for some time, suddenly spoke.

　　南希沉思半晌后，突然開口說話。