—Where did you get this book? —I picked
题型:选择题
问题:
—Where did you get this book?
—I picked it up from a second-hand bookshop if you ______ know.
A.must
B.will
C.can
D.shall
—Where did you get this book?
—I picked it up from a second-hand bookshop if you ______ know.
A.must
B.will
C.can
D.shall