一全文逐句语法解读
本课围绕 浇花园，重点是 have to / must 的区别（客观需要 vs 主观认为）与 need to 的用法。
¶ 1 · have to 与 must（句 3、4、5、11）
| 句子 | 语法点 |
|---|
| I must water the garden first. | 必须 must 着重说明主观看法 |
| Do you have to water it now? | have to 强调客观需要，疑问句用助动词 do |
| I had to water it every day. | have to 的过去式是 had to（不得不） |
| I'm afraid I must. | 简略回答：I must. / I have to. |
¶ 2 · need 与 by oneself（句 12、18）
| 句子 | 语法点 |
|---|
| you don't need to water the garden. | need to do 表“需要做”；否定式为 don't need to |
| I'll have tea by myself. | by oneself = 独自，亲自 |
| Look out of the window. | look out of = 从……向外看 |
¶ 3 · 感叹与判断（句 7、8、19）
| 句子 | 语法点 |
|---|
| It's terribly dry. | terribly 是程度副词，表“非常、极其” |
| What a nuisance! | What a + 名词的感叹句，表厌烦 |
| That was a pleasant surprise. | surprise 表“意外的事、惊喜” |
二固定搭配与重点词组
| 短语 | 用法与例句 |
|---|
| have to / had to | 不得不，必须（强调客观）。 |
| must | 必须（强调主观看法）。 |
| need to do | 需要做。don't need to do 则表“不必做”。 |
| by myself | 我自己，独自。也可说 by yourself / by himself 等。 |
| What a nuisance! | 真讨厌！ |
| look out of | 从……向外看。 |
三语法核心总结
核心语法
have to / must / need to
- have to 强调客观需要多一些，must 则着重说明主观看法。
- need to do 表“需要做”，否定式 don't need to 表“不必做”。
- by oneself 表“独自、亲自”，人称变化：by yourself / by himself / by ourselves 等。
- 本课生词 6 个全部嵌入课文句子，无遗漏。