Here are the suggested answers for the blanks:

1. **hospitable**
2. **open**
3. **speak**
4. **myth**
5. **question**

So the completed passage would read:

The Vietnamese are known to be polite, (1) **hospitable** and sensitive. They have a casual and friendly manner. They regard friendship as being very important throughout one's life. They are always (2) **open** to visits from friends. Drop-in visits are welcome. The Vietnamese are very close to their family. When they offer you a gift, the Vietnamese will usually (3) **speak** lightly about it. Even though it is an expensive gift, they may pretend it is of no great monetary value. With (4) **myth** of 4,000 years of civilization, the Vietnamese are proud people who like to recite to a (5) **question** that they are descendants of an angel and a dragon.