Kitty __________(not know) the answer to the question.

Kitty __________(not know) the answer to the question.

didn't know
未说明一般为过去式

didn't know

does not know

您好！
Kitty _____doesn't know _____(not know) the answer to the question.

doesn't know
第三人称单数

didn't know. KITTY 没有回答那个问题..说明这件事已经过去.所以要用过去时.