concentrate on sth怎么用?on加doing可以吗?
concentrate more on 与concentrate much on 都可以吗
be absorbed in 后可以加doing sth.还有focus one's attention on ,on后
concentrate on
怎么用be keen on doing sth.造句
On doing sth
keep on doing sth
put sth on sth可以变成 put sth on doing sth?
be busy doing sth可以用work on替换吗?如果不能区别是什么?急用!
用plan on doing sth造句
用keep on doing sth 造句
spend time on sth 不必非得加 on/in doing sth
Nothing can b_ you if you concentrate on doing something.