This is the 6583rd most frequent Chinese word.
時他們
The phrase "時他們" does not have a clear or standard meaning in Chinese as-is and might be a typo or miscombination of words.
"當時他們" (dāng shí tāmen) means "at that time, they," where "他們" refers to "them" and "當時" denotes "at that time."
當時他們正在學校裡進行活動。
At that time, they were engaged in activities at school.
"每個假日時，他們" (měi gè jià rì shí, tāmen) means "on every holiday, they," where "他們" stands for "they" and "假日時" specifies "during holidays."
每個假日時，他們都喜歡去郊外野餐。
Every holiday, they like to go on a picnic in the countryside.
"我碰巧經過時，他們" (wǒ pèngqiǎo jīngguò shí, tāmen) translates to "when I happened to pass by, they," where "他們" represents "they" and "經過時" signifies "when passing by."