Q:下列兩句的意思有何不同? (1) Class is supposed to begin at 10: 00. (2) Class was supposed to begin at 10: 00.
A:be supposed to 表示的是一種預期 (expectation) 的情況:現在式的 be supposed to 意為「應該」,因此語意上相當於 should 或 ought to (ought to 的語氣比 should 來得強);過去式的 be supposed to 意為「本該發生的事,但實際上卻沒發生」,因此相當於 ......