The flu is such an infectious illness that it can -1--you any time and anywhere. One -2- you can be feeling fine, and the next you can be -3--, burning up, and then shivering again. Soon your -4-- become weak and your body begins to -5-. Once the flu hits you, you just want to -6-- down in bed. Usually, it -7- three to five days, but is often -8-- by another illness. If you’re old or have heart or -9--problems, you’d better get a flu -10-- every year so as to protect against it.