It’s not easy for the expert to ______ pig flu.in humans from regular human seasonal influenza.
| A．distinguish | B．separate | C．identify | D．recognize |
—John has put forward _______ most challenging question for us to answer.
—Yes, it really is. I have never heard _______ harder one.
| A．the; 不填 | B．不填; the | C．the; the | D．a; a |
I often have conversations with John over ______ telephone, while keep in touch with Tom by ______ letter.
| A．不填；the | B．不填；a | C．the；不填 | D．the; a |
The education of ______ young is always ______ hot and serious topic.
| A．不填, 不填 | B．the, a | C．不填, the | D．the, 不填 |
As _______ unemployment is very high at the moment, it’s very difficult for people to find _______ work.
| A．the, 不填 | B．不填，不填 | C．the, a | D．an, the |
Since tasting the excitement of _____ big city life, she never wants to live in _____ country again.
| A．the, the | B．不填，不填 | C．the, 不填 | D．不填，the |