work on doing sth还是work on to do sth?

work on doing sth还是work on to do sth? work on doing sth造句? got an invitation to do sth 还是 on doing sth/in doing sth/of doing sth 是work hard at sth.还是work hard on sth. 有没有work on doing sth这种用法的 live on 后接doing sth 还是to do sth? working on a painting是什么意思?有work on sth/doing sth 的固定搭配吗? On doing sth he is always busy___ (work)是用be busy doing sth还是 be busy with sth hold on to do sth 还是hold on to doing sth hold on to do sth 还是hold on to doing sth on the way to do sth 还是on the way to doing sth hold on to doing sth 还是hold on to do sth 继续做某事用英文怎么说?是carry on doing sth还是carry on with sth 还是carry on with doing sth be keen on后面加什么be keen on后面加doing sth;do sth;还是to do sth? be busy doing sth可以用work on替换吗?如果不能区别是什么?急用! spend on sth 等于spend doing sth 有spend.on doing sth