--Be careful! You might fall into the water.--Thank you. I.I so close to the pool.A. didn

问题补充：

--Be careful! You might fall into the water.

--Thank you. I.I so close to the pool.

A. didn know; am standing

B. don know; am standing

C. didn’t know; was standing

D. didn know;Would stand

答案：

A. didn know; am standing

B. don know; am standing

(答案→)C. didn’t know; was standing

D. didn know;Would stand

解析：句意：小心，你可能会掉进河里面。——谢谢你，我不知道。我站得离池子太近了。结合语境可知下文前一句指的是刚才的动作，故用一般过去时态。后一句指的是刚才一直在进行的动作，故用过去进行时态。选C。