VOA慢速英语:You Really Should Learn Modals!

短语讲解：

1. There are about 17 modals in English — grammar experts do not agree on an exact number.

agree on 对某事[物]有同样看法， 商定[同意]某事
例句：They agree on these terms.
他们一致同意这些条款。

2. It can be used to express certainty, such as, "He should be here by 5 o'clock."

be used to 习惯于，适用于
例句：This will be used to multiply each term.
它被依次用来乘每一项。

3. Sometimes ought to sounds more like "otta" as in this romantic song by Al Green.

ought to 理应; 应当，应该
例句：He ought to have kept his promise.
他原本应该遵守自己的诺言。

4. Oh for — I'll send up some help.

send up 发射; 使向上升; 毁坏
例句：Please send up a boy to help me with my luggage.
请派一位服务生上来帮我拿行李。

5. In other words, "If you don't run, you will miss your flight."

in other words 换句话说; 就是说
例句：In other words, menus provide a pedagogic vector.
换句话说，菜单是一条学习的途径。