Câu hỏi:

Read the followingpassage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions.

      Cigarettes contain toxic substances like tar and nicotine. That is why we often hear people telling us that smoking is harmful to our bodies. Smoking weakens our lungs as well as other parts of our body. We will not be as active as before and will need more effort to move about.

Smoking affects our environment too. When we puff, we pollute the environment with smoke. This makes our surroundings unpleasant and unclean. Since smoking does not do any good to us, we should always say no to cigarettes. We should advise our loved ones to take a sweet instead whenever they feel like taking a toxic puff.

Smoking is harmful to us because it ______.