Ⅰ. already. adv. “已经”多用于肯定句中,通常与动词的完成时或进行时连用。也可用于疑问句,但不表真心的疑问,而表“惊奇”。它多置于句中。有时为了强调而置于句末。如:
① I’ve seen the film already.
② The train has already left. 火车已经开走了。
③ Have you already had breakfast? 难道你已经吃过早餐了?
Ⅱ. yet adv “已经、仍然、还”一般只用于否定句或疑问句,且常常置于句末。如:
① He hasn’t found his bike yet他还没有找到他的自行车。
Ⅲ. still adv “仍然、还”可用于各种句中,且一般只用于句中。如:
① Do you still teach in that school? 你还在那所学校教书?
[注]:still在句中的位置不同,其意义也不同。如:
① He is still(还)standing there.
② He is standing there still(adj.不动的、静止的)他站在那儿一动也不动。