一、實義動詞,有具體的詞彙意義,表示主語發出的動作或所處的狀態。在陳述句中,實義動詞可以單獨作謂語。實義動詞加表語(主補)、賓語或狀語構成謂語部分。
She is an English teacher and she works hard. (單詞動詞作謂語)
He enjoys swimming and gave us a performance last Sunday. (單詞動詞作謂語)
Mr Smith has been teaching in a middle school for 30 years. (加助動詞作謂語)
(二)情態助動詞具有不同的情態意義。(will會,將, would會,將 shall將, should應該 can可能,也許, could可能 may也許, might可能 muts必須,一定, have / had to不得不 used to過去常常, need需要, dare敢, ought to應該...)
如:I haven't received his letter for a whole month. (加haven't構成完成時態)
Something must be done to make the rivers clean.