The letter c makes a hard sound (like k) in some words, but a soft sound (like s) in others. For example:

city (soft c)

cat (hard c)

The way we pronounce the letter c in a word usually depends on the letter that comes straight after the c.

If the next letter is e, i or y, the c is usually soft.

cent   cinema   cylinder

If the next letter is a, o or u, it is usually hard.

cake    conker    cup