Complete the sentences with the most suitable words: There are ... saving methods and inventions to use solar energy

Complete the sentences with the most suitable words. (15 pts)
6. There are_______ saving methods and inventions to use solar energy.
    A. energetic        B. energize        C. energy        D. energetics
7. I had to pay much money this month for the international_______.
    A. calls            B. calling        C. to call        D. called
8. She is very tired; _______, she has to finish her homework.
    A. moreover        B. so            C. and            D. however
9. She forgot_______ off the gas before going out.
    A. turn            B. turning        C. to turn        D. turned
10. I suggest_______ money for the poor people in our neighborhood.
    A. save            B. to save        C. saving        D. saved        
11. Can you tell me the reasons for_______ the Mother’s Day?
    A. celebrating        B. celebration        C. celebrate        D. celebrated
12. What activities do you want to_______ in at school and at the club?
    A. taking part        B. taken part        C. take part        D. took part
13. I live in Dalat, _______ is one of the most beautiful cities of Vietnam.
    A. who            B. which        C. whom        D. whose
14. The people_______ live in Greece speak Greek.
    A. which        B. whom        C. where        D. who
15. Tet is a festival_______ occurs in late January or early February.
    A. who            B. which         C. whom        D. when
16. This newspaper is_______ every day. It’s a daily newspaper.
A. publishing        B. published        C. to publish        D. publish
17. He is tired_______ he stay up late watching TV.
A. so            B. because        C. but            D. and
18. We are talking about the preservation of_______ resource.
A. natural        B. naturally        C. nature        D. naturalize
19. I will be_______ if she manages to sell that motorbike at a high price.
A. surprise        B. surprised        C. surprising        D. to surprise
20. Unless you understand, I_______ explain it again to you.
A. am            B. was            C. will            D. would.