________ walk is expected to last all day，so bring ________ packed lunch.
| A．A；a | B．The；/ | C．The；a | D．A；/ |
Wash your hands with soap and water ___ after each contact with the sick person.
| A．occasionally |
| B．thoroughly |
| C．scarely |
| D．enough |
After the fun he has had during the holidays, the boy can’t ___ on his schoolwork.
| A．try |
| B．concentrate |
| C．take |
| D．depend |
Jim went to answer the phone. ___, Harry started to prepare lunch.
| A．However |
| B．Nevertheless |
| C．Besides |
| D．Meanwhile |
Clinical evidence began to ___, suggesting that the new drugs had as wider range of useful activities than had been predicted from experiments in animals.
| A．operate |
| B．strengthen |
| C．approve |
| D．accumulate |
He had his camera ready ___ he saw something that would make a good picture.
| A．even if |
| B．if only |
| C．in case |
| D．so that |