13. I'm rather old-fashioned. I know nothing about the new dance steps.
我都跟不上时代了，我对新舞步一点都不懂。
还能这样说：
I am out of fashion and don't know anything about the new dance steps.
I am outmoded and poor at the new dance steps.
应用解析：
lead sb. a merry dance 给某人造成极大麻烦;
dance attendance up on sb. 侍候某人，听其差遣;
dance to sb.'s tune 听从某人指挥
14. Are you keen on dancing?
你擅长跳舞吗?
还能这样说：
Are you good at dancing?
Can you dance well?
应用解析：
as keen as mustard 极热心的，极热情的;
keen on sth. 热衷于某事物，喜爱某事;
keen to do sth. 喜欢做某事
15. It will spice up the party if you dance a solo dance.
你跳个独舞会给聚会添彩。
还能这样说：
Your solo dance will add to the brightness of the party.
Your solo will make a good addition to the party.
应用解析：
spice sth. with sth. 用香料给某物调味
16. Now let us sing and dance and be merry.
现在让我们高高兴兴地唱歌跳舞吧。
还能这样说：
Let us enjoy singing and dancing.
Let's sing and dance happily.
应用解析：
make merry 欢宴作乐，庆祝，行乐;
merriment 欢乐，欢笑;
merry-maker 寻欢作乐者;
make merry over 嘲弄
17. He's a good dancer.
他的舞跳得很好。
还能这样说：
He does well in dancing.
He dances very well.