Here are the suggested answers for the questions based on the text provided:

**For Questions 19 to 24:**
- **Question 19:** A. gain
- **Question 20:** B. focus
- **Question 21:** A. However
- **Question 22:** C. although
- **Question 23:** B. for difficult
- **Question 24:** C. from

**For Question 25:**
The closest sentence is:
**C. Our visit to our grandparents lasted two years.**

**For Question 26:**
The closest sentence is:
**C. I wish Sam would participate in the national heritage preservation campaign.**

**For Questions 27 and 28:**
**Question 27:**
D. If I had enough money with me now, I would buy that coat.
**Question 28:**
A. The doctor asked him to cut down on sweet food/drinks.

Feel free to ask any further questions!