Swim的过去式是swam。

不规则动词变化口诀如下：

1. Go – went

2. Be – was/were

3. Have – had

4. Do – did

5. Say – said

6. Think – thought

7. Get – got

8. Eat – ate

9. Drink – drank

10. Sleep – slept

例句：

1. I went to the park yesterday.（我昨天去了公园。）

2. She was happy when she received the gift.（当她收到礼物时，她很高兴。）

3. They had a great time at the party.（他们在聚会上玩得很开心。）

4. He did his homework last night.（他昨晚做了作业。）

5. She said she would come tomorrow.（她说她明天会来。）

6. I thought it was a good idea.（我认为这是个好主意。）

7. They got to the station on time.（他们准时到达了车站。）

8. He ate breakfast at 7:00 a.m.（他早上7点吃了早餐。）

9. She drank a glass of water.（她喝了一杯水。）

10. They slept for 8 hours last night.（他们昨晚睡了8个小时。）