题干
I’ll lend you the money only on ______you can pay ______on time.
A：condition that;it back
B：condition that;for it
C：one condition;for it
D：one condition;it back
答案(点此获取答案解析）
A
（t为参数），曲线C1： 
（θ为参数）．
该反应进行最快的是