int start, n, pos;
cout << "当前秒数（0-59）: ";
cin >> start;
cout << "经过多少秒: ";
cin >> n;

pos = ____________; // L1
if (____________) // L2
    cout << n << "秒后回到12点方向" << endl;
else
    cout << n << "秒后指向" << pos << "秒刻度" << endl;