usefully解释为：ad 有用地
usefully详细解释
adv. 有用地
例句与用法：
It is a useful book and, what is more, not an expensive one.
这是有用的书，更难得的是不贵。
It's more useful to learn modern languages, such as English and German, than Latin.
学习英语和德语等现代语言比学习拉丁语更为有用。
John always tries to cultivate people who are useful to him.
约翰经常设法和对他有用的人结交。
This book is a storehouse of useful information.
这本书里汇集了大量有用的资料。
He's a useful member of the team.
他是该队的一名强手。
This reference book is very useful to our study.
这本参考书对我们的研究很有用。
She is a useful person to know.
她是个应该结交的有用的人。
词形变化：
副词: usefully |名词: usefulness |
详细释义：
ad.
有用地; 有效地
