This is the 713th most frequent Chinese word.
一個
"One" or "a" (used as a measure word or article).
The word '一個' is used here as a numeral and a measure word to indicate one piece of the countable noun 'apple'.
我有一個蘋果。
I have an apple.
In this sentence, '一個' serves as an introductory numeral and measure word for the singular noun 'decision', emphasizing its importance.
這是一個重要的決定。
This is an important decision.
Here '一個' indicates a single instance or example of an explanation, implying a specific response.