1. however表示“無論如何，不管怎樣”時，其後通常要接形容詞或副詞，意思是“無論多麼……”“不管怎樣……”。如：
People always want more, however rich they are. 人總是富了還想再富。
I refuse, however favorable the conditions are. 不管條件如何有利，我都不幹。
However hard I worked, she was never satisfied. 無論我多麼努力地工作，她從來沒滿意過。
A grammar rule, however true it is, is useless unless it can be understood. 一條語法規則，不管如何正確，除非能懂，否則毫無用處。
I’d rather have a room of my own, however small it is, than share a room. 無論房間多麼小，我寧願一個人住一間，也不願意與別人合住一個房間。
另外，however 還引導方式狀語從句。做連詞，引出一個句子如：
The painting looks wrong however you look at it. 這張畫不論怎麼看都顯得不對勁。
This was a selling job, however you look at it. 不管你怎麼看待這個工作，它還是個銷售的工作。
2.somehow 是副詞，跟however很類似，下面是牛津高階解釋
somehow
/ ˈsʌmhau; ˋsʌmˏhaʊ/ (US also someway/ ˈsʌmweɪ; ˋsʌmˏwe/) indef adv
in some way; by some means 以某種方式; 透過某種途徑:
We must stop him from seeing her somehow. 我們得想個辦法不能讓他再 跟她來往.
Somehow we must get to Glasgow. 我們得設法到格拉斯哥去.
for a reason that is unknown or unspecified 由於未知的或未確指的原因:
Somehow, I don"t feel I can trust him. 不知什麼緣故, 我覺得不能信任他.
I always knew I"d get the job, somehow. 也不知為什麼, 我總是覺得我能得到那份工作.
somehow ：不知何故，莫名其妙的。。 somewhat：稍微, 有點, 有些
兩者都是副詞，用法是一樣的，只是含義上的區別。
The details are supposedto be secret but somehow leak out.
這些細節原屬秘密，可是不知怎麼給洩露出去了。
The natural environment is usually a somewhat balanced ecosystem.
自然環境通常是個比較平衡的生態系統
1. however表示“無論如何，不管怎樣”時，其後通常要接形容詞或副詞，意思是“無論多麼……”“不管怎樣……”。如：
People always want more, however rich they are. 人總是富了還想再富。
I refuse, however favorable the conditions are. 不管條件如何有利，我都不幹。
However hard I worked, she was never satisfied. 無論我多麼努力地工作，她從來沒滿意過。
A grammar rule, however true it is, is useless unless it can be understood. 一條語法規則，不管如何正確，除非能懂，否則毫無用處。
I’d rather have a room of my own, however small it is, than share a room. 無論房間多麼小，我寧願一個人住一間，也不願意與別人合住一個房間。
另外，however 還引導方式狀語從句。做連詞，引出一個句子如：
The painting looks wrong however you look at it. 這張畫不論怎麼看都顯得不對勁。
This was a selling job, however you look at it. 不管你怎麼看待這個工作，它還是個銷售的工作。
2.somehow 是副詞，跟however很類似，下面是牛津高階解釋
somehow
/ ˈsʌmhau; ˋsʌmˏhaʊ/ (US also someway/ ˈsʌmweɪ; ˋsʌmˏwe/) indef adv
in some way; by some means 以某種方式; 透過某種途徑:
We must stop him from seeing her somehow. 我們得想個辦法不能讓他再 跟她來往.
Somehow we must get to Glasgow. 我們得設法到格拉斯哥去.
for a reason that is unknown or unspecified 由於未知的或未確指的原因:
Somehow, I don"t feel I can trust him. 不知什麼緣故, 我覺得不能信任他.
I always knew I"d get the job, somehow. 也不知為什麼, 我總是覺得我能得到那份工作.
somehow ：不知何故，莫名其妙的。。 somewhat：稍微, 有點, 有些
兩者都是副詞，用法是一樣的，只是含義上的區別。
The details are supposedto be secret but somehow leak out.
這些細節原屬秘密，可是不知怎麼給洩露出去了。
The natural environment is usually a somewhat balanced ecosystem.
自然環境通常是個比較平衡的生態系統