Here’s how you can underline the words with /f/ and double underline the words with /fr/ in the sentences provided:

1. The **flowers** in the vase fill the room with **fragrance**.
2. He **frowned** when he saw the broken frame of his bicycle.
3. Nga often misses school because she gets the **flu** frequently.
4. Can you check the **fridge** to see if we have any fresh eggs left?
5. The **flight** was delayed due to technical issues, which made passengers **frustrated**.
6. For dinner, we had a delicious meal of fried chicken with a side of **fresh** fruit salad.
7. During the flood, we had to rely on our **flashlight** to find our way around the house.
8. My parents removed the old carpet from the floor and replaced it with hardwood.
9. The chef prepares the breaded chicken by coating it in **flour** before frying it.
10. Kim spotted a beautiful butterfly resting on a bright yellow **flower**.
11. I want to borrow a book from the library about French history.
12. My sister **frequently** practises the **flute** to improve her skills.
13. As I watched the **flamingo**, a dragonfly flew past, creating a picturesque scene.
14. Parents' behaviour often reflects their influence on their children's upbringing.
15. Last Friday, I came to my friend's house and her friendly dog greeted me with a wagging tail.

Feel free to under underline and double underline these words accordingly!