题干
It's windy and cold _________ winter _________ Beijing.
A：on; at
B：on, in
C：in; on
D：in, in
答案(点此获取答案解析）
D
It's windy and cold _________ winter _________ Beijing.
A：on; at
B：on, in
C：in; on
D：in, in
的方程 
的两根同为负数，则（ ）。