Sure! Here are the corrections for each sentence:

1. Khue Van Pavilion is regarded **as** the symbol of Ha Noi.
2. Today, the Temple **is** considered one of the most popular tourist attractions.
3. I **have** never been to Hanoi before.
4. The students were not interested in history because it **was** boring. (No correction needed if referring to past; otherwise, use "is" for present.)
5. Tourists should add the Temple of Literature to their **visit** list in Hanoi. (Should be "itinerary" or "schedule.")
6. You’d better take your raincoat because it’s going to **rain**. (No correction needed.)
7. The **Doctors'** stone tablets were first erected by King Le Thanh Tong. (No need for an apostrophe if referring to multiple doctors.)
8. The Imperial City of Hue was finally completed under the reign of King Minh **Mang**. (No correction needed; just ensure consistent spelling.)

Let me know if you need more help!