I can't find my book ,I think I _____ it on learn English well.

问题描述:

I can't find my book ,I think I _____ it on learn English well.
I can't find my book ,I think I _____ it on my way home just now.
A,dropped B,borrowed C,posted D,bought

A,我不能找到我的书,我认为它刚才在我回家的路上掉落了.drop意为掉落,其过去式为dropped.