一全文逐句语法解读
本课把 现在进行时 从「一个人正在做」扩到 一群人/多个场景，并用 There be 句型先交代「有什么」再描写「正在怎么样」。
¶ 1 · 天气描写与 there be（句 1-2、5）
| 句子 | 语法点 |
|---|
| It is a fine day today. | 说天气用 it 作主语：It is a fine day / It is hot. 不能说 Today is a fine day |
| There are some clouds in the sky, but the sun is shining. | There be 先交代存在；but 连接两个相反画面；shine → shining |
| There are some boats on the river. | 复数用 There are；on the river 在河上 |
¶ 2 · 现在进行时描写连续画面（句 3-10）
| 句子 | 语法点 |
|---|
| They are walking over the bridge. | walk over 走过；over 表「在……上方、越过」 |
| Mr. Jones and his wife are looking at them. | look at 看；主语是两人 → are |
| The ship is going under the bridge. | under 在……下面；与 over 相对 |
| The aeroplane is flying over the river. | fly → flying；over 表从上方掠过 |
¶ 3 · 介词 over / under / on / in 的位置感
| 句子 | 语法点 |
|---|
| over the bridge | 在桥上方、越过桥 |
| under the bridge | 在桥下（穿过桥洞） |
| on the river | 在河面上（船、桥等贴着水面） |
| in the sky | 在天空中（立体空间内） |
二固定搭配与重点词组
| 短语 | 用法与例句 |
|---|
| a fine day | 晴天。It is a fine day today. 今天天气好。 |
| in the sky | 在天空中。There are some clouds in the sky. 天上有些云。 |
| be with sb. | 和某人在一起。Mr. Jones is with his family. 琼斯先生和家人在一起。 |
| walk over the bridge | 走过桥。They are walking over the bridge. 他们正在过桥。 |
| look at | 看……。Sally is looking at a big ship. 莎莉正在看一艘大船。 |
| fly over | 飞过。The aeroplane is flying over the river. 飞机正从河上飞过。 |
三语法核心总结
- There are 用于复数；单数才用 There is。
- shine → shining：以不发音 e 结尾的动词去 e 加 -ing（make → making）。
- 介词别混：over（越过上方）/ under（下方）/ on（表面）/ in（内部）。
- 本课生词 15 个全部嵌入课文句子，无遗漏。