1)It is + no use, no good (fun, a great pleasure, a waste of time, a bore...)等名词+doing sth. It is no use crying.哭没有用。
It is no good objecting.反对也没有用。
It is a great fun playing football.打篮球很有趣。
2) It is + useless (nice, good，interesting, expensive等形容词)+ doing sth.
It is useless speaking.光说没用。
It is nice seeing you again.真高兴又遇到了你。
It is good playing chess after supper.晚饭后弈棋挺好。