Regarding Siem Reap in Puzhai, who can tell me how a 4-star hotel in Cambodia looks like a standard room, how about environmental sanitation service and breakfast, and why it is 4.5 stars?

This still depends on the specific hotel, and there will be differences in the same 4-star hotel. Of course, if you want to compare with domestic four-star hotels, it is definitely not as good as domestic hotels. Before going to Cambodia, I stayed in a 5-star hotel (Angkor Paradise Villa) and four people lived in the villa together. The environment is good, and the breakfast is not bad.