입니다 used in positive sentence and 입니까? Used fn negative sentence So 사랑합니다 means 'I love you' and 사랑합니까? Means ' am I love you'....

A verb(including adjective) in formal declarative sentences end with "-다", and "-까" is added instead of "-다" when questioning.:) e.g. This is an apple = 이것은 사과입니다.(formal) Is this an apple? = 이것은 사과입니까? I love you = 나는 당신을 사랑합니다. Do you love me? = 당신은 저를 사랑합니까? \^o^/

'입니다' is declarative sentence. '입니까' is Interrogative sentences . Here is an example.. 사랑입니다. (This is love) 사랑입니까? (Is this love?) 사랑합니다. (I love you) 사랑합니까? -> '사랑합니까?' needs an object. (사랑합니까? /그남자를/그녀를/무엇을?) (Do you love him/her/or something?) ^^