我可以去下外面儿么? -->我可以出去一会儿么？

1.郊 and 部 have complete different meanings. 郊 means suburb (e.g. 城郊 - suburb area of the city) and 部 means part or ministry.(e.g. 一部分 - a part of；交通部 - Ministry of Transportation) 2.I usually everyday do this work? This is not correct even in English. I can understand what you were trying to say though, 通常我每天都做这项工作 - Usually I do the work everyday. 3. 我想我家人 - Yes. I miss my family. 那家饭馆儿 - Yes. That restaurant (colloquially) 我可以去一下外边吗 - Remove that 儿 then it will be correct 4. 盖 and 建 are the same when they refer to "to build". “盖” is more vivid, to pile up a building floor by floor like a sandwich. Besides, 盖 has more meaning as a verb.