ld take 4-6 months before thefirst batchofvaccines areavailable to fight A/H1N1 flu ________ as swine flu, WHO officials said.

________ will you stay in Shenzhen for your summer vacation?—For about two weeks.

Never before______ so highly successful inhis attempts to forecast the weather accurately on a small scale．

The boy sitting by the window is the onlyone of the studentswhofrom the countryside in our school

It was not until 1911, _______ the first vitamin was identified, _______ people realized the importance of it．