问题
By now, more than 100 photos ________ back to the earth by Chang’e-3
A:had been sent
B:y now, more than 100 photos ________ back to the earth by
C:have been sent
D:will be sent
B:y now, more than 100 photos ________ back to the earth by
C:have been sent
D:will be sent
正确答案是：
