I.1 quickly

2 quietly

3 happily

4 beautifully

5 well

6 loudly

7 carefully

8 well

9 angrily

10 completely

II.1 Because Mr.Juan only has a little money, he buys a cheap car 

2 Because she wanted to major in English she chose Vietnam National University

3 Your parents would be very happy because you passed the exam

4 Because they begin to jog, most people think jogging is a good exercise.

5. He was late for school because of his broken bike.

III.1 We are delighted that everyone enjoys our homemade cakes 

2 He is so pleased that his parents are waiting at the school gate to take him home

3 I am so haapy that my brother got a safe flight

4 We are afraid that we can't join the party with you

5 I am so sorry that I lost your favourite pen on my way home

IV.1 will give

2 find

3 don't keep/will

4 know

5 gives/will you do