25. He suggested using fewer plastic bags.

S + suggested + Ving: đề nghị 

26. Nga wants to go home because she feels sick.

S số ít + Vs/es

want + to V: muốn 

27. I am disappointed that you didn't phone me.

S + be + ADj + that + clause 

S + didn't + V1: thì QKĐ

28. If we plant more trees, we will have more shade and fresh air.

If 1: If + HTĐ, S + will / can /shall + V1 

`color{orange}{~MiaMB~}`

25. He suggested using fewer plastic bags

- S + suggested + V - ing: Gợi ý làm gì

26. Nga wants to go home because she feels sick

- Want to + V - inf: Muốn ... 

- Feel(s) + adj: Cảm thấy thế nào

27. I am disappointed that you didn't phone me

- Adj - ed diễn tả cảm xúc người

- Disappointed ( a ): Thất vọng

28. If we plant more trees, we will have more shade and fresh air

- Đk loại 1: If + S + V(s/es), S + model verbs ( HT ) + V - inf