purpose

1.for charitable purposes，for military purposes，for practical purposes，for instruction purposes等表达方式里用复数形式purposes。

2.for (the) purposes of travel，for (the) purposes of medicine等表达方式里的the用的少，不用的多。注意用复数形式purposes。

3.my purpose in writing this book，his purpose in going to Australia等表达方式里用in，不用of。the purpose of writing this book，the purpose of going to Australia等表达方式里用of，不用in。不可说the purpose of my writing this book等。

4.purpose（动词）后面接不定式或动名词都可以。例如：I purpose to devote（或devoting）myself to the cause from now on.和I purpose to give（或giving）the committee all the details.用不定式比用动名词普通。也可以接以that引导的从句，那从句里用shall。例如：We purpose that such disasters shall not occur again.