While other scientists are keeping____eye on changes in the H5N1 bird flu strain, the scientists in England are working on vaccines, in case it becomes highly infectious in ____humans.
We were in _____ when we left that we forgot the airline tickets.
If there were no hungry problem, the people of the world should have ________ in their daily life.
The big snow lasted five days.People trapped in the station were badly in_______ of food and water.
In some places in the South of China, ____car has already become___ popular means of transportation.
Yao Ming as well as his teammates ______ hard to win honor for China these years.