Scientists say it may be five or six years _____ it is possible to test this medicine on human patients.
He has given us a suggestion __________ we shouldbuy a cottage in the country with the money we have saved.
There's no __________ in the way they do their accounts(记账).
There are too many difficulties for us __________. Wereally don't know __________ to do.
You'll find taxis waiting at the bus station __________ you can hire to reach your host family.
Thetest measures mathematical __________.