首先,這句話有語法及用詞錯誤.應(yīng)該是:
He often goes to walk except on rainy days.
他常去散步,除非下雨.
這里的except不是介詞,而是連詞,意思是除非.這樣用時,如果去掉except,句子語法結(jié)構(gòu)還是對的,但是意思正好被反過來:
He often goes to walk on rainy days.
顯然如果沒有介詞on,語法就錯了.類似的例子還有:
They didn't open their mouths except to complaint.
他們一開口就抱怨.
except后面跟句子的時候,也是連詞,不是介詞,相當(dāng)于but.如:
I’d go and see him myself, except I don’t know where he lives.
這里把except換成but,意思完全一樣.
except后面跟that, when, if從句的時候,那個從句不是except的賓語,而是句子里其它部分的賓語或其它成分.except在這里仍然是連詞.如:
I don’t know much about the man, except that he’s a fool.
這里的從句that he's a fool是動詞know的賓語.
He often goes to walk except when it rains.
這里的從句when it rains是狀語.