D) I am so terribly sorry., would be the most formal.
China.
The Silk Road is a trading route from the Middle East to China, and the ancient civilizaitons practiced ancestor worship. The Mandate of Heaven dictates that good weather and general prosperity are because of divine approval of the leader of China. If there is famine, invasion, or other natural disasters, it was interpreted as needing a new ruler, aka losing the mandate of heaven.
Answer:
improving air quality :
1. keep it clean. a clean house may be a healthier house , because good indoor hygiene can greatly cut down on dust and animal dander
2. keep the greenery outdoors
3. change your filters
4. invest in an air purifier
5. let fresh air in
Um I think you swapped B and C around but it would be COMPONENTS OF A HOUSE. A house has many things in it and need to have certain things in it to stand up. Like in some cases there needs to be support. In others it can support itself.
