2．however

　　(1)作副词时，表示"然而，可是，不过"，用以引出令人吃惊或表示对比的话语，可放在句首、句中或句末，但要用逗号隔开。

　　I'd like to go with you, however, my hands are full.

　　我很想和你一块去，可是我太忙了。

　　You may be right.However, I still want to do what I planned.

　　你也许是对的，但我还想按我计划的去做。

　　(2)作连词时，表示"无论如何，不管怎样"，相当于no matter how，引导让步状语从句，从句可放在主句之前或之后。常构成：however/no matter how ＋adj./adv.＋主语＋谓语。

　　However late he is，his family will wait for him to have dinner together.

　　无论多晚，他的家人总是等他一起吃晚饭。

　　3．although/though

　　(1)although和though都是引导让步状语从句的从属连词，意为"尽管，虽然"，一般情况下可以互换。但although较正式，多用于句首，而though在非正式文体中较为普遍。although和though都不能和并列连词but连用，但可以和yet或still连用(因为yet和still是副词而不是连词)。

　　Although/Though he is in poor health, (yet) he works hard.＝He is in poor health，but he works hard.

　　虽然他身体不佳但是他工作很努力。

　　(2)though引导让步状语从句时可用部分倒装形式，其用法相当于as，把从句中的表语、状语或动词原形置于句首；若表语是可数名词单数，前置时要省略不定冠词。

　　Poor though/as he is, he lives a happy life.

　　他虽然穷，但过得很幸福。

　　Child though/as she is, she knows a lot.

　　虽然还是个孩子，她却懂得很多。

　　Much though/as he loved her, he didn't tell her.

　　尽管他很爱她，但并没有告诉她。

Try though/as I might, I couldn't lift the stone.