一、The simple present (一般现在时)
1.一般现在时表示经常发生、习惯性动作、客观真理、科学事实、格言，目前的特征、状态、能力等。(与一般现在时连用的时间状语有：every day, once a week, always, often, every time, now and then, occasionally, seldom, sometimes, usually, etc.)
The earth moves （move） around the sun.
Columbus proved that the earth is （be） round.
