First Advertisement: Modern Education in Vietnam

Question 1: How has (1) education changed in Vietnam over the years?

Answer: B. the (Education refers to a specific system or concept that has already been mentioned or is known, hence "the" is appropriate).

Question 2: Have you tried (2) different ways to study or used (3) electronic devices for your homework?

Answer: A. different (You are referring to various ways, so "different" is needed here).
Answer for 3: A. electronic (As it refers to electronic devices, the adjective "electronic" is correct).

Second Advertisement: Discover How Vietnam Has Changed!

Question 1: Join us at (1) Cultural Center, 456 Heritage Road, Hanci.

Answer: A. a (The Cultural Center is not a specific one previously mentioned, so we use the indefinite article "a").

Question 2: Join us at the Cultural Center (2) Hanoi on September 20 for a journey through Vietnam's transformation from the past to today.

Answer: C. in (The event is taking place in a city, so "in" is the correct preposition).

Question 3: Don't miss this chance to (3) more about Vietnam's rich culture.

Answer: A. learn (The infinitive verb "learn" is needed here to complete the sentence).

Third Advertisement: Healthy Living in Vietnam!

Question 1: Have you adopted (1) healthy habit recently?

Answer: C. an (You are referring to one healthy habit, so "an" is the correct indefinite article).

Question 2: Share how you've integrated (2) physical activities or nutritious meals into your routine.

Answer: A. in (Physical activities are integrated in your routine, so "in" is the correct preposition).

Question 3: What (3) changes have you noticed in your well-being?

Answer: A. positive (The adjective "positive" fits correctly to describe the changes).