语法点：动词后接 -ing 与不定式 (Verb + -ing vs Verb + to)
英语里一个动词后面再接另一个动词时，第二个动词要么变成 -ing 形式（动名词），要么用 to + 动词原形（不定式），由第一个动词决定。有些动词只能接 -ing（admit、enjoy、finish、mind、avoid），有些只能接 to（want、decide、try、hope、refuse），还有一些两者都可以接（begin、start、like）。此外，动词或形容词后面如果有介词（at、of、for、about），介词后面的动词一律用 -ing。本课中 began to unload、try to run away、admitted hiding、at being discovered 正好把这几种情况都体现出来了。
结构
| 类型 | 常见动词 | 例句 |
|---|---|---|
| 动词 + to do | want, decide, try, hope, refuse, learn, begin | He did not even try to run away. |
| 动词 + doing | admit, enjoy, finish, mind, avoid, keep, suggest | The man admitted hiding in the box. |
| 动词/形容词 + 介词 + doing | be surprised at, be astonished at, account for, think of | He was surprised at being discovered. |
| 两者皆可（意思基本相同） | begin, start, like, love | Workers began to unload / began unloading the boxes. |
否定形式：try not to run away / admitted not hiding。 被动形式：being + 过去分词，如 at being discovered。
课文中的例句
- [句 1] …workers began to unload a number of wooden boxes which contained clothing. — begin + to do，也可说 began unloading
- [句 2] No one could account for the fact that one of the boxes was extremely heavy. — account for 后接名词 the fact，若接动词则用 -ing
- [句 3] It suddenly occurred to one of the workers to open up the box. — it occurred to sb. to do，不定式作真正的主语
- [句 6] He was so surprised at being discovered that he did not even try to run away. — 介词 at 后接被动动名词 being discovered；try + to do
- [句 7] After he was arrested, the man admitted hiding in the box before the plane left London. — admit 后只能接 -ing，不能接 to
补充例句
- The man admitted stealing the woollen goods. — 那人承认偷了毛织品。
- The workers decided to open the heavy box. — 工人们决定打开那个沉箱子。
- He was astonished at finding a man inside. — 他发现里面有个人，大吃一惊。
易错点
- ❌ The man admitted to hide in the box. → ✅ The man admitted hiding in the box. — admit 后面只能接 -ing 形式，不能接 to do。
- ❌ He was surprised at be discovered. → ✅ He was surprised at being discovered. — 介词 at 后面的动词必须用 -ing，被动就是 being + 过去分词。
- ❌ He did not even try running away. → ✅ He did not even try to run away. — try to do 表示"设法做"；try doing 是"试着做做看"，这里应用 to do。
- ❌ It occurred to one of the workers opening the box. → ✅ It occurred to one of the workers to open the box. — it occurred to sb. 后面用不定式 to do 作真正主语。