Which cities are host cities?
select t1.city from city as t1 join hosting_city as t4 on t1.city_id = t4.host_city
Okay, which cities have not hosted?
select city from city where city_id not in ( select host_city from hosting_city )
Great! Out of those cities, which ones have temperatures lower in March compared to their December temperature?
select t1.city from city as t1 join temperature as t2 on t1.city_id = t2.city_id where t2.mar < t2.dec except select t3.city from city as t3 join hosting_city as t4 on t3.city_id = t4.host_city
Oh, sorry! Yes, which city has the lowest temperature in March?
select t2.mar,t1.city from city as t1 join temperature as t2 on t1.city_id = t2.city_id where t1.city = "Hangzhou ( zhejiang ) " or t1.city = "Nantong ( jiangsu ) "