题干
Flowers usually come out ______ spring every year.
A：in
B：at
C：on
D：of
答案(点此获取答案解析）
A
Flowers usually come out ______ spring every year.
A：in
B：at
C：on
D：of
2C(g)；△H＞0。下列反应条件有利于生成C的是（ ）