break的匹配问题

for n in range(2,10):
    for x in range(2,n):
        if n%x ==0:
            print(n,'equals',x,'*',n//x)
            break
    else:
        #loop fell through without finding a facter
        print(n,"is a prime number")
程序中的break对应的是上面的if还是for?