The discovery was made in the 1950s, while the ________ of it was not recognized until half a century later.
This is not the way ____ we did the test last time.
As the mid- examination is coming , the students are busy ____ it.
—You were brave enough to raise objections at the meeting. --Well , now I regret ____that.
Bamboo grows best in the place _____ it is warm and rains often.
–Did you ask the guard what happened? --Yes, he told me all ______ he knew.