Unit 8 Immunization

Bài 1: Chia động từ trong ngoặc theo thì thích hợp

Điền dạng đúng của động từ trong ngoặc vào chỗ trống.

1. Immunization __________ (be) an effective method of preventing infectious diseases.
2. Scientists __________ (modify) bacteria and viruses before using them in vaccines.
3. If a person __________ (come) into contact with a disease-causing agent, the immune system immediately __________ (respond).
4. Immunization __________ (dramatically reduce) the incidence of many deadly diseases over the past decades.
5. In 1980, a worldwide vaccination program __________ (result) in the eradication of smallpox.
6. Since 1988, the number of cases of hemophilus influenzae type B meningitis __________ (drop) significantly.
7. The World Health Organization __________ (set) the year 2000 as a target for global immunization.
8. Some vaccines __________ (provide) lifelong protection, while others __________ (require) booster shots.

Bài 2: Chọn đáp án đúng

Chọn đáp án đúng để hoàn thành câu.

1. Immunization __________ the body’s immune system to build a defense mechanism.
   a) triggers
   b) trigger
   c) triggering
2. Scientists __________ new vaccines to combat infectious diseases.
   a) develop
   b) are developing
   c) have developed
3. Since 1988, the number of cases __________ significantly.
   a) drops
   b) has dropped
   c) is dropping
4. By the time a child reaches school age, they __________ immunized.
   a) will be
   b) were
   c) have been
5. In 1980, smallpox __________ eradicated worldwide.
   a) is
   b) was
   c) has been

Bài 3: Viết lại câu bằng cách sử dụng các thì khác nhau

1. Immunization has reduced the incidence of deadly diseases. (Chuyển sang quá khứ đơn)
   → ________________________________________________________
2. Scientists are developing new vaccines. (Chuyển sang thì hiện tại hoàn thành)
   → ________________________________________________________
3. In 1980, a worldwide vaccination program resulted in the eradication of smallpox. (Chuyển sang thì hiện tại hoàn thành)
   → ________________________________________________________
4. Some immunizing agents require repeated inoculations. (Chuyển sang thì tương lai đơn)
   → ________________________________________________________
5. The WHO has set a target for global immunization. (Chuyển sang thì tương lai hoàn thành)
   → ________________________________________________________

Bài 4: Điền từ đúng vào chỗ trống

Điền từ thích hợp vào chỗ trống với “since”, “for”, “already”, “yet”, “just”.

1. The number of cases has dropped significantly __________ 1988.
2. Scientists have __________ developed new vaccines to fight diseases.
3. The WHO has worked on global immunization __________ many decades.
4. Have they discovered a cure for this disease __________?
5. A worldwide vaccination program has __________ resulted in the eradication of smallpox.