Oh, Brother!
A few days ago I read an article on the internet  about common grammar mistakes. The text said that “My brother and I went to the White House” was a mistake and that the correct use was “my brother and me.” I have always used the first (because I thought it was the correct form). Am I wrong? Thanks in advance.
Sabrina

No, you are right! The correct form is “My brother and I went to the White House” because “My brother and I” are the subjects of the sentence. Many people do say “My brother and me” but this is considered incorrect (at least by grammar purists). “My brother and me” is grammatically correct only when “My brother and me” are the objects of the sentence. For example: “At the White House the security guard was very rude to my brother and me.”

Jobs offered
I recently read an ad for a job that  asked for candidates who were “able to hit the ground running” and who “must have a muck in attitude.” But what does that mean?  
Monica

To hit the ground running means to start work immediately and to get busy without a long period of training, briefing or preparation. It is a military term: paratroopers (soldiers with parachutes) who hit the ground running start running (and fighting) as soon as their parachute lands: they don’t stop or rest after their big jump. Instead they go straight into action.
To muck in means that you are an individual with good team spirit. To “muck in” literally means to share accommodation and food with other people, and help clean the house and do other domestic chores and generally work hard without complaining.