昨天我打电话来的时候，你在干什么？

What were you doing when I called you yesterday?

Source: Tatoeba

Sentence Composition

1 昨天 zuótiān yesterday
2 我 wǒ
  1. I
  2. me
  3. my
3 打电话 dǎdiànhuà to make a telephone call
4 来的 láide
  1. (regional, chiefly Cantonese-influenced Mandarin, colloquial) synonym of 來著 /来着 (láizhe)
  2. at; in
  3. synonym of 來著 /来着 (láizhe)
  4. to be at; to be in; to exist
  5. used to indicate the continuous aspect
5 时候 shíhou
  1. time
  2. length of time
  3. moment
  4. period
=6 你 nǐ you (informal, as opposed to courteous 您 nín)
=6 你 nǐ you (Note: In Taiwan, 妳 is used to address females, but in mainland China, it is not commonly used. Instead, 你 is used to address both males and females.)
7 在 zài
  1. to exist; to be alive
  2. (of sb or sth) to be (located) at
  3. (used before a verb to indicate an action in progress)
8 干什么 gànshénme
  1. what are you doing?
  2. what's he up to?