13. The board was unsure ______ the proposed strategy would yield measurable results within the quarter.
(A) of
(B) whether
(C) that
(D) if or not
答案:登入後查看
統計: A(1), B(19), C(2), D(1), E(0) #3492651
統計: A(1), B(19), C(2), D(1), E(0) #3492651