ten commandments
4 Cardinal Points of the Compass
21 Consonants in the Alphabet
2 covers on a book
7 Continents in the World
This is a Ditloid. The answer is 7 Colours in a Rainbow.
7 C in the W = 7 Continents in the World.
10 Christmas cards in a set of cards
32 Degrees Fahrenheit is Freezing Point (of Water)
10 Centuries in a Millenium
1st Confession by Frank O'Connor
4 corners on a tetrahedron.