信马由缰

tā fàng rèn zì jǐ de sī xù xìn mǎ yóu jiāng

他放任自己的思绪信马由缰。

He allowed his mind to wander.

tā de xíng wén què shí yǒu xiē xìn mǎ yóu jiāng yào shi jiǎn jié yī xiē jiù hǎo le

它的行文确实有些信马由缰，要是简洁一些就好了。

It would have been best written in a more concise way as it does tend to ramble.

wèi le xiāo qiǎn wǒ ràng zì jǐ de sī xiǎng xìn mǎ yóu jiāng

为了消遣，我让自己的思想信马由缰。

For entertainment I let my thoughts wander.