Joseph, the politician who（　）last week, has been released unharmed.

A:is kidnapped B:was kidnapped C:has been kidnapped D:had been kidnapped

（）more careful, such spelling mistakes might have been avoided.

A:You had been B:You have been C:Had you been D:Have you been

Joseph, the politician who ______ last week, has been released unharmed.

A:is kidnapped B:was kidnapped C:has been kidnapped D:had been kidnapped

These compounds could not have been formed if the chemical reaction ______ stopped.

A:have been B:has been C:had been D:were

These compounds could not have been formed if the chemical reaction ______ stopped.

A:have been B:has been C:had been D:were

______more careful, such spelling mistakes might have been avoided.

A:You had been B:You have been C:Had you been D:Have you been

________, everything would have been all right.

A:He had been there B:Been here he had C:Here he had been D:Had he been here