Links importantes:

http://www.mairovergara.com/
https://www.duolingo.com
http://isfaluno.mec.gov.br/
http://englishlearners.com.br/livros-em-ingles-nivel-intermediario/

Quando usar start/begin?

Begin é mais usado para algo que é frequente e start para algo que não é.

Ex: I begin working at nine in the morning every day.
Ex: I started working when I was 14 years old.

Start: máquinas (ligar)

Would rather/would prefer

Would rather and would prefer are used to express a preference.

Ex.: Ana would rather travel than stay home