Here are the correct forms of the words in brackets:

1. What is your **height**? (HIGH)
2. Lan was absent from class because of her **sickness**. (SICK)
3. We must remember to eat **sensibly**. (SENSE)
4. One of the most important **inventions** is the computer. (INVENT)
5. Eating too much sugar is **unhealthy** for your life. (HEALTH)
6. The regular **activities** of our school is English Speaking Club. (ACT)
7. A balanced diet means you eat a **variety** of foods without eating too much of anything. (VARI)
8. Vietnamese grammar is **different** from English one. (DIFFERENCE)