-I didn't hear you come just now.
-That's good. We tried __________ any noise, for you were sleeping.
A:not make
B:not to make
C:to make
D:Making
(Ⅰ)求C1,C2的标准方程;
(Ⅱ)是否存在直线L满足条件:①过C2的焦点F;②与C1交与不同的两点M,N且满足 OM→⊥ON→ ?若存在,求出直线方程;若不存在,说明理由.