今天是第一天。

Today is the first day.

Source: Tatoeba

Sentence Composition

1 今天 jīntiān
  1. today
  2. the present time; now
=2 是 shì
  1. to be (followed by substantives only)
  2. correct; right; true
  3. (respectful acknowledgement of a command) very well
  4. (adverb for emphatic assertion)
=2 是 shì variant of 是 shì
=3 第一 dìyī
  1. first
  2. most important; primary; foremost
=3 第一 dì-yī
  1. (literally, figuratively) first; 1st
  2. being the most important consideration; being essential, or a priority; coming first
  3. first; 1st
  4. firstly
  5. number one; #1; first (in a test, competition, etc.)
4 天 tiān
  1. day
  2. sky
  3. heaven