请问应填but还是although?谢谢

请问应填but还是although?谢谢 ___ if a bird can do it,anybody can do it.是填Although还是But 括号里应该填but,还是应该什么都不填：Although they feel tired.( ) they still we look the same,we aren't twins 填but 还是although?、为什么? He has no brothers ____ daughters应填or还是but although和BUT Although he is very old,( )he works very hard 中能不能填but 老师，although什么情况下能与but连用？谢谢老师！！ although和but的问题 nationality应填china还是chinese Much ______I like the car,I can't afford it.是填although 还是as This is a pen( )that is a pencil.填空,填and或but.请问要填哪一个啊?是“和”还是