I can't remember __________ I put the book,and I need it for my homework now.A.where B.how C.what D.why

I can't remember __________ I put the book,and I need it for my homework now.A.where B.how C.what D.why
I can't remember __________ I put the book,and I need it for my homework now.
A.where B.how C.what D.why

I can't remember __________ I put the book,and I need it for my homework now.A.where B.how C.what D.why
A
我记不起我把书放哪里了.