25. After many years’ tough talks, Vietnam became the 150th member ________ the WTO last year.
| A．joining | B．having joined | C．to join | D．Joined |
The world today _____ different without the amazing discoveries produced by great scientists.
| A．were | B．had been |
| C．would be | D．would have been |
No one knows for certain how the first Americans arrived in _____ is now the United States.
| A．which | B．what | C．where | D．why |
A journal is not necessarily a reliable record of facts, for the writer’s impressions _____ colour the telling of events.
| A．must | B．shall | C．should | D． might |
She seated herself at a small table in the restaurant, waiting _____.
| A．serving | B．to serve |
| C．served | D．to be served |
Most online classes let students learn _____ their own pace.
| A．at | B．to | C．from | D．by |