英語中副詞主要起修飾動詞,形容詞,其他副詞和整個句子的用法。所以當我們用一個詞來修飾整個句子,並放在開頭的時候,一般都用該單詞的副詞形式。例如
Luckily ,I have got the chance to be teaching in the best school in my province.
Unluckily, he failed in the important exam.
Luck在句子開頭用副詞形式,是因爲luckily修飾的是後面的動詞,例如Luckily,he was not hurt badly.