Wang Wei had served ______a volunteer for three years before he graduated from college .
| A．as | B．for | C．at | D．in |
Experts say walking is one of the best ways for a person to _______ healthy.
| A．handle | B．stay | C．maintain | D．reserve |
_______ unexpected heavy rain usually causes _______ great change.
| A．The; the | B．An; 不填 | C．An; the | D．The; a |
---It’s getting late. I am afraid I must be off now.
---_______!
| A．Go slowly | B．So long | C．No problem | D．All right |
Many British people have noticed that butterflies _______ from its natural habitats during the past several years.
| A．are disappearing | B．have been disappeared |
| C．have been disappearing | D．will have disappeared |
---What a nice day!
---Yes. I like _______ when the weather is fine.
| A．one | B．that | C．it | D．this |