19. They haven’t _____ an AIDS vaccine.
(A) yet developed
(B) developed already
(C) developing
(D) developing yet
(E) already developing

答案：登入後查看
統計： A(197), B(21), C(10), D(12), E(14) #820509

詳解 (共 1 筆)

#3227463
They haven’t _____ a...
(共 212 字，隱藏中）
前往觀看
17
0