Danny left word with my secretary _______ he would call again in the afternoon.
Leaves are found _______ all kinds of trees, but they differ greatly ________ size and shape.
To save class time, our teacher has ________ students do half of the exercises in class and complete the other half for our homework.
Now an increasing number of middle school students go abroad for further study at their own ________, trying hard to realize their dreams.
Darwin counted 225 flowering plants, ________ he collected and brought home 193.
The government has taken some measures to reconstruct the earthquake-hit areas, but it must be some time ________ everything returns to normal.