3.Why did the alarm go off? Someone may ______ one of the emergency doors by mistake.
(A) open
(B) be open
(C) have opened
(D) had opened
答案:登入後查看
統計: A(128), B(39), C(215), D(126), E(0) #1831844
統計: A(128), B(39), C(215), D(126), E(0) #1831844