They are still very cautious about ________ side effect the new medicine will bring about, although the experts have tried it on about 2000 patients.
Europe has achieved more in controlling the AIDS virus than Asia in the past ten years, ________ the number of people infected with the virus is going up sharply.
With the development of agriculture, the people ________ village I taught are now living a happy life.
The archaeologists found gold coins and pottery in the lowest level of the site ________ they reached three months ago.
Gone are the days ________ we spent together in the mountainous village.
________ is known to us all, our government has spared no efforts to control food prices.