A group of 7 musical notes is made into a 7 -tone musical phrase, consisting of 7 different notes. How many different phrases are possible to construct?

Step 1 ：This is a permutation problem. We have 7 different musical notes and we want to arrange them in a 7-tone musical phrase. The order of the notes matters, so we use the formula for permutations of n distinct items taken r at a time, which is nPr = n! / (n-r)!. In this case, n = r = 7, so the formula simplifies to 7!.

Step 2 ：Substitute n = 7 and r = 7 into the formula, we get the number of phrases as 5040.0. However, the number of phrases should be an integer, so we convert the result to an integer.

Step 3 ：Final Answer: The number of different 7-tone musical phrases that can be constructed from 7 different notes is \(\boxed{5040}\).