记忆卡片

Present perfect describes an action or state that started in the past and retains an active link to the present moment. This connection appears in four regular ways: an action that creates an immediate result, a life experience without a fixed date, a condition continuing across time, or an event within an unfinished time frame. The auxiliary verb shows present time, while the participle carries the event.

The delivery van has arrived outside, so we can unload the boxes.