I am looking forward to going to Tian'anmen this Spring Festival with you. 我盼望着这个春节能和你去天安门。

I'm afraid but I only have three days free. 对不起，我可能只有有三天空闲时间。

When will you have time on earth? 你到底什么时候有时间?

When can we happen to be free at the same day? 什么时候我们能正好同一天有空?

Maybe we can go there next time. 也许我们可以下次去那儿。