一般来讲是join the army 还是 join army 还是join an army

一般来讲是join the army 还是 join army 还是join an army 是join in army还是 join in a army? 是join the army（陆军）还是take part in army（陆军）? serve in the army和join the army的区别比如serve in the army是完成时里的,只是状态.join the army是现在或将来的,表动作, My brother has ( )( )( )of the army for five years.原句是join the army five years ago. It is ten years since he ____(join) the army Jim isn't old e() to join the army.(军队) How long before did he join the army?改错. How long before did he join the army?改错 join in the army里的in为什么要去掉 My brother_（join）the Army lost year determined men shoud join the army这句英语是什么意思 Are you old enough to join the army? 她以一个男人的身份加入军队用英语怎么说she join the army as a man?she join the army with the identity of a man she join the army with the identity as a man?哪个是对的?半吊子就不要误人子弟了 参军是enter the army还是enter into the army enter,join,take part in区别enter the army=join the army 为什么?enter a contest=take part in a contest 请问为什么？ Jim isn't old e___ to join the army .=Jim is t___ young to join the army.中该填什么单词? He join the army when he was fifteen(保持原句意思）He join the army__ __ __ __fifteen.