Ex1:

1/ Oo: classic, picnic

2/Ooo:medical, national, chemical, physical, classical, logical

3/oOo: dramatic, athletic, artistic, historic,

4/oOoo: grammatical, political

5/ooOo: scientific, 

Ex2:

1/pollution   2/contamination   3/death     4/poisonous   5/polluted

Ex3: 

1/worked -> has worked
because ->so

2/because of -> because

3/in->to

4/to ->in

5/cause ->make

Ex4:

1/C

2/D

3/A

4/C

5/D

6/A
Ex5:

a)

1 - C

2 - E

3 - B

4 - A

5 - F

6- Từ Forcus này sai nha phải là Focus - D

b)

1/ Because there was so much grafffiti  on the building's walls.

2/he/she felt insecure.

3/Because she thought they might fall down

4/he/she was busy with her/his assingements

5/ It caused she/he so much stress that she/he don't want to study.

6/She/he decided to clean the room and put her/his things  in theirs proper place. She/ he also bought a small plant ...

Ex6:

1/T

2/T

3/F

4/T

5/F

6/T

Ex7:

1/B

2C

3/D

4/A

5/B

6/C

7/A

8/D

9/B

10/B