And to be clear, you can't "cure" influenza either because it is a virus (which is not living like bacteria are), like the common cold. In my limited medical understanding, drugs like Tamiflu work by breaking down the protein shell of the virus that allows the enzymes to function.

Richard,

Many of your sentence suggestions do not include verbs. A better way to say it is, "How does the common cold differ from influenza?" or, more commonly, "How is the common cold different from influenza?" Most of the English speaking population would not use the word differentiate in general conversation. 

Drowen,

I'm not sure how to answer this since I am not a doctor, but generally influenza is accompanied by chills, fever, hot or cold sweats, congestion, phlegm, and/or cough. The common cold is usually just drainage, congestion and sneezing or coughing, and rarely includes a fever or other symptoms. Influenza is a virus that can be shortened if caught early with drugs such as Tamiflu; the common cold can only be treated to lessen symptoms, not as an actual cure.

Saturday at the beach? No, I'm studying English.

T.G.I.S. A good day to watch some videos about "how to improve in English". Yesterday, I (I don't know what you mean here) about a friend. He studied with me in high school and loves English. We talked about this and he showed me some methods that he uses to learn, especially a blog and a game. And, as we all know, on the Internet, link to link, we discover many things. I discovered many Brazilian blogs that support your learning with tips and tricks.
In addition (or you can use "Also"), I talked with a boy I knew here, and the conversation was nice, and, despite my mistakes, it flowed very well :)
In short, I'm very happy with my progress and very excited about the discoveries!!!

For today this is enough :D