1) Obligation and prohibition; strong advice a) should b) could c) may d) must 2) Polite request; Possibility a) may b) should c) must d) could 3) Advice; probability a) may b) could c) must d) should 4) Ability or lack of ability; Informal request a) must b) should c) could d) can 5) An ability that existed in the past or a suggestion a) may b) should c) could d) must

modal verbs

列印
嵌入

排行榜

視覺風格

選項

切換範本

恢復自動保存: ?