Question

4. The reports went missing in 2012 and nobody     them since.

A. sees      B. saw

C. has seen   D.  had seen

Answer 1

4.    C考查动词的时态。句意：那些报告2012年就丢失了，从那以后没有人见过它们。since在此处意为"从那以后"，这是现在完成时的标志。故选C。