We must __________ that the experiment is controlled as rigidly as possible.
Only by increasing the number of doctors by 50 percent ________ properly in this hospital.
Look! The ground is wet. It must have rained last night, ________?
I told Mom that not everyone could manage to have 3 meals on time everyday, ________?
No sooner ________ down on bed ________ the telephone rang.
Honey, you ________ alcohol for they have stopped drinking.