### V. Tense

1. **D. visited**  
   (The sentence is referring to a past action, so the past simple tense is needed.)
   
2. **C. uses**  
   (The sentence is in the present simple tense, and since the subject is "a boy" (third person singular), we need "uses.")

3. **A. are chatting**  
   (The action is happening now, so the present continuous tense is correct.)

---

### VI. Structures

1. **A. load**  
   (The correct verb to describe the action of placing rice onto the cart is "load.")

2. **A. more convenient**  
   (The comparative form of "convenient" is "more convenient.")

3. **D. surfing**  
   (After verbs like "dislike," we use the gerund form of the verb, which is "surfing.")

4. **C. better**  
   ("Better" is the correct comparative form of "good.")

5. **C. less**  
   ("Less" is used to compare the quantity or degree of something, and medical help is less easily obtained in remote areas.)

---

### VII. Word Form

1. **B. interested**  
   ("Interested" is the correct adjective form to describe someone who has an interest in something.)

2. **C. usually**  
   (The correct adverb form to modify the verb "walk" is "usually.")

3. **A. relaxed**  
   ("Relaxed" is the correct adjective to describe how David feels after doing leisure activities.)

---

 

Tense:

1. They _________ Ho Chi Minh City last summer.
   D. visited

2. If a boy _________ his strength to frighten weaker peers, he is a bully.
   C. uses

3. Now they all _________ with each other more frequently than before because they have smartphones.
   A. are chatting

 

Structures:

1. Duy helps his parents ______________ the rice onto the ox-drawn cart.
   A. load

2. Is living in the city ______________ than living in the country?
   A. more convenient

3. Ben dislikes _______ the Net in the evening.
   D. surfing

4. Elsa plays the guitar ______________ than Jenny does.
   C. better

5. Medical help is ______________ easily obtained in big cities than in remote areas.
   A. more

 

Word form:

1. Nam isn’t _____________ in using Facebook at night.
   B. interested

2. Tom and Tim _______ walk to school together.
   C. usually

3. David feels ______________ when he does leisure activities in his free time.
   A. relaxed

A. for - We use "for" to indicate a duration of time. (They visited Ho Chi Minh City for last summer)

V. Tense

1. D. visited - The action happened and is finished in the past. (They visited Ho Chi Minh City last summer)
2. C. uses - This is a present tense statement about a habitual action. (If a boy uses his strength...)
3. A. are chatting - This is a present tense statement about an ongoing action. (Now they all are chatting with each other...)

VI. Structures

1. A. load - "Load" is the verb that makes sense in this context. (Duy helps his parents load the rice...)
2. A. more convenient - This is the comparative form of "convenient." (Is living in the city more convenient than living in the country?)
3. D. surfing - The gerund form "surfing" is used after the verb "dislike." (Ben dislikes surfing the Net...)
4. C. better - "Better" is the comparative form of "good" used for non-descriptive adjectives. (Elsa plays the guitar better than Jenny does)
5. A. more - "More" is used as a comparative adjective before a countable noun "help." (Medical help is more easily obtained...)

VII. Word form

1. B. interested - The adjective "interested" describes Nam. (Nam isn't interested in using the Facebook at night)
2. C. usually - "Usually" is an adverb describing how often they walk. (Tom and Tim usually walk to school together)
3. A. relaxed - "Relaxed" is the adjective describing how David feels. (David feels relaxed when he does leisure activities...)

 

1.C
2.B
3.A
4.D
5.C

Here are the correct answers for each question:

**V. Tense**
1. D. visited
2. C. uses
3. A. are chatting

**VI. Structures**
1. A. load
2. A. more convenient
3. D. surfing
4. C. better
5. C. less

**VII. Word form**
1. B. interested
2. C. usually
3. A. relaxed

Let me know if you need any further assistance!