______visited the Shanghai World Expo is sure to tell you the place is worth visiting twice.
| A．Those who have | B．Whoever has |
| C．Those who has | D．Whoever have |
While other scientists are keeping____eye on changes in the H5N1 bird flu strain, the scientists in England are working on vaccines, in case it becomes highly infectious in ____humans.
| A．a , / | B．an, / | C．the, an | D．an, the |
---John, there is ______ Mr. Wilson on the phone for you.
---I'm in ______ bath.
| A．a; the | B．the; a | C．a;不填 | D．the;不填 |
The teacher, with 6 girls and 8 boys of her class, _______ visiting a museum when the earthquake struck.
| A．was | B．were | C．had been | D．would be |
All the employees except the manager ______to work online at home.
| A．encourages | B．encourage | C．is encouraged | D．are encouraged |
____with the size of the whole earth , the biggest ocean does not seem big at all .
| A．Compare | B．When comparing | C．Comparing | D．When compared |