1. Ill be going to work on foot while my bicycle------.
(a) is being repaired (b) is repaired
(c) will repaired (d) has been repaired
2. The radar sets------for a long time without any trouble.
(a) have been running (b) have been run
(c) have run (d) were running
3. While the ice box------, a lot of defects were found.
(a) was being examined (b) was examined
(c) was examining (d) had been examined
4. Do you remember------to Dr. Henry during your last visit?
(a) to be introduced (b) being introduced
（c）having introduced (d) to have introduced