______ it have been the failure to pick up directions from the ground control that caused the air crash?
| A．Must | B．Could | C．Would | D．Should |
In the questionnaire, the subjects are questioned whether they______ banning cars in the city center.
| A．agree | B．comment | C．advocate | D．conduct |
The explorer traveled to several remote villages, _____a lot of unusual information.
| A．gathering | B．having gather | C．to gather | D．gathered |
All the candidates were ______ the street to be named after a great man ______ his great contributions to the city.
| A．in favor of; in need of | B．in praise of; in favor of |
| C．in praise of; in need of | D．in favor of; in honor of |
When the headmaster spoke out his plan, the _____of the students in the class ____ against it.
| A．majority; were | B．most; were | C．most; did | D．majority; did |
______ by many well-known experts and film stars, the product was very popular at one time.
| A．To advocate | B．Having advocated | C．Advocating | D．Advocated |