This tool is very useful.
这个工具非常有用。
She found the guide useful.
她发现这个指南很有用。
A map is always useful.
地图总是很有用。
That advice was quite useful.
那个建议相当有用。
His tips are really useful.
他的提示真的很有用。
This app is extremely useful.
这个应用程序非常有用。
Keeping notes can be useful.
做笔记可以很有用。
Her experience is useful.
她的经验很有用。
The checklist is useful.
这个清单很有用。
These instructions are useful.
这些说明很有用。
useful load
有效载荷
make oneself useful
做对人有利的事
be useful
有用；有益；（to/for）对...有用
be useful to
对...有益；有用；有助于
useful information
有用信息
比较级: more useful;
最高级: most useful;
副词: usefully;
