八年级下册英语第一单元的句子主要包括以下内容，综合多个版本教材整理如下：

一、日常交际类

1. What's the matter with you？ = How's your day going？ = What's wrong with you？

2. I should lie down and rest. = I need to rest.

3. How did you go to school yesterday？ = What did you do last weekend？

二、建议与建议类

1. You should take my temperature. = I think you should measure your temperature.

2. You shouldn't eat too much. = You need to cut down on food.

3. You should do eye exercises. = It's good for your eyes.

三、健康相关类

1. I have a headache. = My head hurts.

2. I have a stomachache. = My stomach hurts.

3. I have a toothache. = My tooth hurts.

四、习惯建议类

1. Don't talk too much. = Keep quiet.

2. Drink enough water. = Stay hydrated.

3. Practice makes perfect. = The more you practice, the better you'll get.

这些句子覆盖了日常交流、健康建议、习惯培养等常见场景，建议结合语境进行记忆和运用。如需具体例句或听力材料，可参考教材配套资源。