When I passed the house, I saw him __________ and didn't disturb him.
Scientists say it may be five or six years _______ it is possible to test this medicine on human patients.
---Mike, please don’t forget to turn off the light when you leave.---Pardon?---I ________ forget to turn off the light.
It is so nice to hear from her. _______, we last met more than thirty years ago.
Could you tell me __________ the railway station?
It was because of the bad weather ______ the sports meet was put off.