He was told that it would be at least three more months ______he could recover and return to work .
Rare species in the world, ______ by hundreds every year, must be jointly preserved by all countries, or humans will encounter ecological disaster in the near future.
It a Saturday afternoon in May ______ Margaret could arrange for me to meet her elder sister.
I failed in the examination last term and only then ____ the importance of studies.
________ he had won the first prize, he felt very happy.
It is not immediately clear __________ the housing price will go down.