Dưới đây là 3 ví dụ cho mỗi cấu trúc bạn yêu cầu:

### 1. to be kind to sb
1. She is always kind to her younger sister.
2. It's important to be kind to animals.
3. He was very kind to the new students at school.

### 2. difficult for sb to do sth
1. It is difficult for her to learn a new language.
2. This math problem is difficult for him to solve.
3. It can be difficult for kids to understand complex concepts.

### 3. decide + toV
1. They decided to go on vacation next month.
2. She decided to study abroad for a year.
3. He has decided to start a new project at work.

### 4. S + have/has + not + Vp2 + O + before → chuyển thành: this is the first time + S + have/has + Vp2
1. **She has not traveled abroad before.** → This is the first time she has traveled abroad.
2. **They have not visited that museum before.** → This is the first time they have visited that museum.
3. **He has not eaten sushi before.** → This is the first time he has eaten sushi.