Lots of good questions here! 1) You would use "at the moment". It indicates that right now, something is or isn't true. In your example, the chair isn't there. Another more common use would be "I'm busy at the moment- can I call back later?" 2) This is a fun nuance of the English language. "Down" is an extra word in this sentence. The phrase "down here" just means the speaker is referring to a place he isn't familiar with. Example: If you lived in the northern part of the USA and I lived in the southern part and you called me and asked "Is it raining down there?", I would say "No, is it snowing up there?" 3) In this sentence "take off" means to gain popularity or begin to do well. I believe it's a shortening of the saying "take off running". It can also mean "leave" or in the context of work "have time off"