—When did your cousin begin to show his interest in medicine?—It was a Saturday __________ she noticed her uncle experimenting on a frog in his lab.
When her servant left to have a baby, Lady Susan had to turn ___ cook.
After the long-distance running race, we students returned home, ___________.
This is the very plan for our May Day holiday _______ was made by our classmates.
Is _____ necessary to take off our shoes when we enter the computer lab?
____ matters most in learning English is enough practice.