Leaves are found _______ all kinds of trees, but they differ greatly ________ size and shape.
We have various summer camps for your holidays; you can choose __________ based on your own interests.
The employment rate has continued to rise in big cities thanks to the efforts of the local governments to increase __________.
After they got __________,he never remarried. 【选项】
If you have trouble in communicating with others, it's bound __________ your study.
The factory now employs __________.