3 sentences

1. 我常常回想童年的快乐时光。

   wǒ cháng​cháng huí​xiǎng tóng​nián de kuài​lè shí​guāng.

   I often think back on the happy times of my childhood.

   Source: Dong Chinese Dictionary

2. 人生的很多经历回想起来如梦一般。

   rén​shēng de hěn​duō jīng​lì huí​xiǎng qi​lai rú mèng yī​bān.

   Looking back, many experiences in life feel like a dream.

   Source: Dong Chinese Dictionary

3. 回想起孩提时代的往事，他总是忍不住微笑。

   huí​xiǎng qǐ hái tí shí​dài de wǎng​shì, tā zǒng​shì rěn bù zhù wēi​xiào.

   Whenever he recalls his childhood memories, he can't help but smile.

   Source: Dong Chinese Dictionary