in a verb group of two or more words, we usually place an adverb of indefinite time or an adverb of frequency after the first word in the verb group.<----這是說明的
例子: i have already finished my work.
she has rarely been outside the house since her illness.
他說already and rarely都是adverb
但是我做下面這一條不明白點解不正確
a. shan studies usually late at night.
b. yesterday shan studied late at night.
c. shan always studies late at night.
得b c是正確.....點解a是錯的