With ____ leaves ____ in the earth every year, the soil becomes richer and richer.
. We _______ have proved great adventures, but we have done the greatest march ever made in the past ten years.
All the people in the nation can remember exactly how many years ago _______ the civil war broke out.
_______ difficult the task may be, we must finish it on time, because we can’t meet such a precious opportunity _______ we have expected.
The earthquake in Yushu, Qinghai Province damaged many houses and business buildings; _______, it caused more than 1,000 deaths.
Catherine bought a postcard of the place she was visiting, addressed _______ to _______ and then posted it at the nearby post office.