Translation of Stiftschraube

I try to learn English as much as possible so that I can travel next year to the United States. I would agree to your proposal but I also need to find good teachers. My goal is quality and speed.
And in the end you still have not learned what you have wanted. I browse in online stores all day and come back empty-handed, or with items that I do not really need. Learn and think about it.
I am back in Switzerland, and the weather makes me crazy. Shall I write you on Vocabulix or to your regular email address? I have been working 20 years as an employee for a German company.