There was something wrong with the network, or the e-mail earlier.
A. could have been sent
B. might be sent
C. need have been sent
D. must be sent
网友回答
(答案→)A. could have been sent
B. might be sent
C. need have been sent
D. must be sent
解析：考查隐含的虚拟语气：句意：网络有问题了，否则电子邮件可能早就被送到了。这里的or相当于=if There hadn’t been something wrong with the network所以主句用could have done，选A。