—What do you think of the Eiffel Tower?

—Splendid. When I was in France, I      it.

A．have visited

B．had visited

C．could visit

D．visited

需要保全证据的情况有两种，一是证据( )；二是证据在以后难以取得。

A．涉及国家秘密和个人隐私

B．因客观原因不能自行收集

C．可能灭失

D．为案外人所掌握