Choose the correct answer

Question 21. I’d like to visit Sơn Đòong Cave to ______  the natural beauty of the world’s largest cave.

    A. float                          B. explore                          C. explode                         D. climb

Question 22. Tourists usually enjoy ______ Victoria Falls Bridge crossing the Zambezi River with a spectacular ______.

    A. visiting - view         B. visit - view                   C. visiting - viewing        D. visit - viewing

Question 23. Dr. Salk and his colleagues found polio vaccination and stopped the spread of the ______  causing the paralytic disease in 1955.

    A. virus                          B. calorie                           C. harm                              D. nutrient

Question 24. Lack of ______  can cause some serious diseases, such as rickets, goiter and cancer.

    A. viruses                      B. organs                           C. nutrients                       D. diets

Question 25. A: Napping can help you relax and improve your mood, but you should be careful with it.
      B: ______________
      A: If you take a nap for more than 20 minutes, you may wake up with dizziness.

  A. When should I take a nap during the day?       B. Can I take a nap in the afternoon?   

  C. Why is napping good for healthy adults?         D. Can you make it clearer?