Aiming to retrieve the Mars rover Opportunity, engineers are imitating Mars surface conditions in a testing laboratory.

单项选择题These data will be of considerable use for identifying and analyzing environmental degradation, and than crafting workable solutions.()

A. /
B. from
C. with
D. to

单项选择题People whose property is stolen should report to the police.()

A. had stolen
B. is being stolen
C. had been stolen
D. has been stolen