The killer was caught at a pub ______ he was surfing the net, ______ relaxed us all.
Samples of blood from Cholera infected patients have been sent to the blood center _______.
After several years of observation, the research group ______ the conclusion that language acquisition is faster when students ______ to the situation where it is spoken.
It will be many years ______the doctors and medical scientists can find _____ for cancer.
We have to ______ everything question in detail ______ we take action.
It is clear that no use can be made ______radium _____we don’t know clearly the characteristics of it.